Marshall, C.J.
Pursuant to G. L. c. 215, § 13,4 and Mass. R. Dom. Rel. P. 64, a judge in the Probate and Family Court reserved and reported four questions concerning the financial obligations of a deceased father’s estate to his minor child:
“1. whether a testator, survived by a minor child to whom he owed . . . support pursuant to a court order, may disinherit that child pursuant to the [omitted child statute,] G. L. c. 191, § 20;
“2. whether the child’s claim for support is in the nature of a preferred creditor’s claim;
“3. whether a posthumous support obligation includes assets of an inter vivos trust; and
“4. whether an order to secure postmajority educational support may be made in the circumstances of posthumous support.”
We discuss the background facts and applicable law before answering the questions.
1. Background. The father died on November 20, 1994, at the age of fifty-five. He was divorced at the time of his death. He was survived by two children, an adult daughter from his only [440] marriage, and a minor child (child) born on September 10, 1990, to the mother, L.W.K. (mother), to whom he was not married. The mother was forty-two years old at the time of the child’s birth. Prior to the father’s death, the mother brought a paternity action to establish him as her child’s father. On June 11, 1992, after a hearing, a judge in the Probate and Family Court so determined, and ordered the father to pay child support of $100 a week to the mother, the order to remain in effect “until further order of the Court.”5 The father paid the required child support until his death.
On June 3, 1994, the father executed a will that disinherited his minor child, leaving to her the amount of one dollar. He further directed that she “shall not be considered as an heir-at-law of mine” nor “a child of mine or issue of mine for any purpose under this will.”6 The will provided that, after the payment of specific monetary bequests and disposition of certain tangible property, the remainder of the estate be devised and bequeathed to a trust (trust) that the father had previously established on February 3, 1977. On the same day the father also signed a final amendment to the trust that restated all of the trust terms.7 The trust instrument authorized the trustees, on the father’s death, to collect various life insurance policies and any devises and bequests made by the father to the trust. The trust named the father’s sister (sister) and his adult daughter (the only child from his quondam marriage) as the sole beneficiaries. [441] After the father’s death, the sister was appointed executrix of his estate. She filed a Federal estate tax return that listed the father’s total gross estate as $800,398, and a taxable estate of $648,722.
On the death of the father, the mother filed a claim for Social Security benefits on her child’s behalf based on the father’s participation in the Social Security system. It was determined that the child, as a qualified minor, was entitled to receive at that time $849 a month in Social Security benefits.8 The child is entitled to receive these benefits until she turns eighteen or until her nineteenth birthday if she has not finished high school. The child is now ten years old. Her mother has the sole responsibility for her care and upbringing. The child’s only source of income is the Social Security benefits, in addition to support from her mother.9
A guardian ad litem, appointed to represent the child’s interests in the father’s estate, filed a complaint for modification of the child support order entered in 1992, and a notice of claim against the estate seeking further support payments for the child.10 Some time later, a petition for authority to compromise was filed in the estate probate proceeding in which the mother and the sister (executrix of the father’s estate) agreed to a settlement of all claims of the child in the amount of $10,000. A second guardian ad litem, appointed to represent the child’s interests, filed an opposition to the compromise.11 After a hearing, the compromise was dismissed and an attorney was appointed to represent the child in the modification action. The judge allowed a joint motion filed by the mother and the executrix to amend the complaint for modification to add the trustees as defendants.
The parties submitted a statement of agreed facts and made a joint request for rulings. The judge ruled preliminarily that (1) the father could not disinherit his minor child to defeat his sup[442] port obligations; (2) the assets of the inter vivos trust and the estate are subject to the child’s support claim; (3) she had the authority to enter an order against the father’s estate for future educational support of the child; and (4) the child’s receipt of Social Security benefits did not bar further claims for support. Because the judge determined that the case presented questions of first impression, and that answers to the questions materially affected the merits of the claim for modification, she reserved and reported four questions and stayed the proceedings pending an appellate ruling. We granted the defendants’ application for direct appellate review.
2. Questions one and two. For ease of discussion we address in tandem the first two questions.
Testamentary freedom is not absolute, and certain preexisting obligations have priority over all testamentary dispositions. See, e.g., Harrison v. Stevens, 305 Mass. 532, 535 (1940) (testamentary dispositions subject to the “claims of creditors and to administration expenses”); G. L. c. 191, § 15, 16 (spousal elective share takes priority over testamentary dispositions). See also H.J. Alperin & L.D. Shubow, Summary of Basic Law § 22.113, at 565 (3d ed. 1996). A legally enforceable obligation to pay child support, like other financial obligations of the testator, takes precedence over testamentary dispositions and must be satisfied prior to any distribution of assets under the will.12 A [443] parent charged with an obligation to support his13 child cannot nullify that legal obligation by disinheriting his child pursuant to G. L. c. 191, § 20.14 Beyond satisfaction of his support obligation, however, a parent is free to exercise his testamentary discretion with respect to a minor child, as all others, and may disinherit her.15
In order to answer questions one and two, therefore, we must resolve whether the order to the father to support his minor child survived his death. Specifically we must decide whether a child support order, made pursuant to G. L. c. 209C, § 9, during the father’s life, creates an obligation on his estate to continue support until his child reaches majority, or whether any obligations for her future support were extinguished by his death.
The duty of a parent to support a minor child is statutory. See, e.g., G. L. c. 208, § 28; G. L. c. 209, § 37; G. L. c. 209C, § 9. The question, therefore, is one of statutory interpretation. We conclude that the death of the father does not extinguish his duty to support his minor child. We do so for several reasons. [444] First, contrary to the dissent, we are not legislating but applying unequivocal policy mandates of the Legislature to the specific facts of this case. For decades extending back into the Nineteenth Century, the Legislature has mandated and this court has recognized that parents have an obligation to support their minor children. The Legislature has expressed that duty in unmistakable terms: “It is the public policy of the commonwealth that dependent children shall be maintained, as completely as possible, from the resources of their parents thereby relieving or avoiding, at least in part, the burden borne by the citizens of the commonwealth.” G. L. c. 119A, § 1, as amended through St. 1998, c. 463, § 101 (approved with emergency preamble, Jan. 14, 1999).16 The Legislature has also decreed that the statutes concerning child support enforcement “shall be liberally construed to effectuate” that public policy. Id.
Second, in this Commonwealth there have been recent and profound legislative changes that have increased significantly the obligation of parents to support their children.17 Federal law has also increased significantly the obligations of parents for [445] child support.18 Thus, both State and Federal law are explicit in providing for the broadest possible support of minor children by their parents. Moreover, under the Child Support Enforcement Act an “[ojbligor” is defined as “an individual, or the estate of a decedent, who owes or may owe a duty of support, or who is liable under a child support obligation,” plainly suggesting that the Legislature intended liability for child support obligations to survive the death of a parent (emphasis supplied). G. L. c. 119A, § 1A. That the child support order was entered in a paternity proceeding other than a divorce proceeding is of no significance, for the Legislature has mandated that children born out of wedlock are entitled to the same rights and protections of the law as all other children. See G. L. c. 209C, § 1, inserted by St. 1986, c. 310, § 16.19
Third, the Legislature has imposed an explicit duty on parents who divorce and those who give birth to children out of wedlock to support their minor child until they attain their majority. General Laws c. 209C, § 1, imposes child support responsibility on a parent from the child’s birth to the age of eighteen, and beyond that period if certain statutory and readily discernible circumstances exist.20 See Doe v. Roe, 23 Mass. App. Ct. 590, 594-595 (1987). See also G. L. c. 209, § 37 (imposing support obligations on separated parents of minor children). Where its terms [446] are unambiguous, a statute must be held to mean what it plainly expresses. See 2A N.J. Singer, Sutherland Statutory Construction § 46.01 (6th ed. rev. 2000). In this case, the child support order is in force until the child is emancipated or “until further order of the Court.” Neither of these contingencies has occurred. We are not free to add a further requirement, beyond what the Legislature has declared, that the father is responsible for the support of his child bom out of wedlock “from [her] birth up to the age of eighteen,” G. L. c. 209C, § 1, but only until his death.21
Our ruling is also consistent with the declared public policy of this Commonwealth “that dependent children shall be maintained, as completely as possible, from the resources of their parents.” G. L. c. 119A, § 1. See G. L. c. 209C, § 20. It would be inconsistent with that and other mandates of the Legislature to conclude that a father’s court-ordered support obligation abated on his death, depriving his young daughter, of the resources necessary for her maintenance. In an intact family, minor children have security against the loss of support when one parent dies, even in the case of testamentary disinheritance, because of the spousal elective share. G. L. c. 191, §§ 15, 16. See also G. L. c. 190, § 1 (spouse’s right to share of property not disposed of by will); G. L. c. 193, § 1 (surviving spouse listed first in schedule of persons entitled to appointment to administer intestate’s estate); G. L. c. 229, § 1 (right of surviving spouse to bring wrongful death action). Children' of divorced parents and children bom out of wedlock do not have the same protection. For this reason, we are unpersuaded by the defendants’ argument that our holding would unfairly discriminate against children from intact families.
Fourth, a conclusion that child support obligations survive [447] the death of a parent is consistent with prevailing contemporary legal authority. See, e.g., Knowles v. Thompson, 166 Vt. 414, 418 (1997), citing Morris v. Henry, 193 Va. 631, 636 (1952) (“text writers and a decided majority of cases hold that under modern conditions liability of the father is not necessarily terminated by his death, and that there is no sound reason, unless prohibited by statute, why his estate should not be charged with his obligation to support his minor children”). See also Edelman v. Edelman, 65 Wyo. 271, 291-292 (1948), in which the Wyoming Supreme Court reached the same conclusion fifty years ago. The Uniform Marriage and Divorce Act § 316 (c), 9A U.L.A. 102 (Master ed. 1998), reflects this prevailing view: “Unless otherwise agreed in writing or expressly provided in the decree, provisions for the support of a child are terminated by emancipation of the child but not by the death of a parent obligated to support the child.’'’ (emphasis added). The comment to that section explains: “[Tjhis section terminates the obligation of a parent to support a child, only upon the child’s emancipation. The parent’s death does not terminate the child’s right to support, and the court may make an appropriate order establishing the obligation of the deceased parent’s estate to the child” (emphasis added). Id. at 103.
Finally, there is nothing in G. L. c. 191, § 20, that prohibits such a construction. That statute “forbids nothing and compels nothing; it merely provides a framework within which private testamentary decisions may be freely made.” Hanson v. Markham, 371 Mass. 262, 265 (1976). Our conclusion interpreting the legislative mandate that child support obligations do not abate at death will not create any uncertainty for estate planning purposes. See Hornung v. Estate of Lagerquist, 155 Mont. 412, 419 (1970) (“the enforcement of an obligation for future support presents no greater problems than any other unliquidated claim against an estate”). Unlike alimony, an order to provide for the support of a minor child terminates at a specific age. Accordingly, the total amount of child support that a parent is obliged to pay may be readily determined — in contrast to an order to provide alimony that in many circumstances terminates only when a spouse remarries (a date uncertain in the future) or on the recipient’s death (similarly uncertain).22
The protection of minor children, most especially those who [448] may be stigmatized by their “illegitimate” status or who are not supported by divorced parents fully capable of doing so, has been a hallmark of legislative action and of the jurisprudence of this court. Consistent with the public policy so clearly articulated by the Legislature, the estate of the father in this case is charged with his court-imposed obligations to support his minor child. Beyond satisfaction of those obligations — which we address further in our discussion concerning question four — the father may disinherit his minor child.
3. Question three. We consider whether the father’s support obligation can be satisfied from the assets of his inter vivos trust. We conclude that all the assets of the inter vivos trust established by the father, under which he was the sole beneficiary entitled to funds at his request, and which he solely retained the power to modify, alter or revoke, must be included in the estate and, as such, must be made available to satisfy his child support obligations. Such a ruling is consistent with our law in closely related areas.
We have held that, for the purpose of determining a surviving spouse’s elective share, G. L. c. 191, § 15, assets in an inter vi-vos trust over which the decedent had a general power of appointment, exercisable by deed or by will, constitute the estate of the deceased spouse. See Sullivan v. Burkin, 390 Mass. 864, 867 (1984).23 The Appeals Court has similarly recognized that creditors can reach the assets of an inter vivos trust to “the maximum amount which the trustee . . . could pay to [the trustee] or apply for his benefit,” in order to satisfy the trustee’s debts to them. State St. Bank & Trust Co. v. Reiser, 7 Mass. App. Ct. 633, 636 (1979). See Nile v. Nile, ante 390 (2000). See also Restatement (Second) of Trusts § 156 (2) (1959); Restatement (Second) of Property § 34.3 (3) comments h, j [449] (1990). Our earlier decisions reason that, as to property that a settlor may appoint to himself or his executors, the property could have been devoted to fulfilling debts or a widow’s “special interests which should be recognized.” Sullivan v. Bur-kin, supra at 869. We see no reason not to adopt the same reasoning for purposes of payment of a child obligation debt, and the defendants offer none.24
4. Question four. We are asked to determine whether an order to secure postminority educational support may be made posthumously. We note, preliminarily, that on a related issue the judge concluded that the Social Security benefits received by the child after her father’s death were not a “substitute” for his child support obligations, but a credit to him. The judge did not report that question to us. However, that issue is inextricably connected to our consideration of the posthumous order to pay some amount for the child’s college education: both issues require us to consider whether the death of a parent warrants reconsideration and possible modification of the original child-support order.
The judge found that the child would be entitled to receive monthly Social Security benefits until her eighteenth birthday, and possibly to the age of nineteen if she has not completed her high school education as of that date. She further found that the child’s mother would be more than sixty years of age at the time the child is ready to enter college and that other than the support the child receives now, “there are no other sources of funds for her present and future needs.” The judge concluded that she had the authority “to set aside a lump sum in trust as security for [the child’s] future educational support if the assets are sufficient,” and that the amount for educational support “may be made contingent upon the child’s eligibility for that award under G. L. c. 209C, § 9.” She noted that “[i]n this way, the estate administration will not be unduly prolonged.” As to the Social Security benefits, she concluded that the benefits “act as a ‘credit’ to the obligor in determining the appropriate amount of support in a modification hearing, and not as a substitute for [450] that support obligation.” Because the order was interlocutory, the judge did not specify any specific sum to be set aside “in trust” as security for the child’s future educational support, nor did she determine the amount of support obligation, taking into account the “credit” of the Social Security benefits.
The judge’s authority to enter or to modify a support order is statutory. G. L. c. 209C, § 20. General Laws c. 209C, § 20, provides in relevant part that a “court with original jurisdiction . . . has continuing jurisdiction, upon a complaint filed by a person or agency entitled to file original actions, to modify judgments of support, custody or visitation”25 (emphasis supplied). See also G. L. c. 208, § 28 (“Upon a complaint after a divorce, filed by either parent or by a next friend on behalf of the children after notice to both parents, the court may make a judgment modifying its earlier judgment as to the care and custody of the minor children . . .”). Because an obligation to provide child support survives the death of a parent, a judge must have the authority to modify any such obligation.26 Our statutes contain no provision that the judge’s “continuing jurisdiction” while a child is a minor is conditional on her parent being alive. Importing such a requirement into the statute [451] would conflict with the overriding public policy clearly articulated by the Legislature we described earlier. In DuMont v. Godbey, 382 Mass. 234, 240 (1981), we held that posthumous modification of an alimony award was permitted (“Probate Court could properly determine what, if any, payments were due after the death of the husband, and could modify its decree not only as to the future, but also as to arrears”). Recognition of posthumous modification of a child support order is more compelling because the express language of G. L. c. 209C, § 20, provides a judge with continuing jurisdiction. See G. L. c. 208, § 28.
The original 1992 support order did not contain any provision for his child’s later educational support. The terms of that order, however, made it subject to further modification, and, as the judge in this case found, in the eleven-year period prior to the paternity action, the father had held several positions of employment commensurate with his educational background and expertise. But at the time of the hearing he characterized his occupational status as “[unemployed.” He was fifty-two years of age at the time, and there is no suggestion that he would not have attained gainful employment subsequent to the paternity adjudication.
A support order may be modified if the judge finds a “substantial change in the circumstances of the parties or the child has occurred and finds modification to be in the child’s best interests.” G. L. c. 209C, § 20. See G. L. c. 208, § 28. While nothing mandates that the death of the parent-obligor automatically results in a “substantial change in circumstances” warranting modification, this case plainly meets that standard. The child now receives Social Security benefits as a result of the father’s death that were not earlier available. Moreover, in contrast to the period before the father’s death, any resources that may be necessary to maintain his young daughter are available only for the limited period during the administration of the estate; beyond that the support order can no longer be changed by “further order of the Court.”
With respect to the effect of the now-available Social Security benefits, we previously have held, along with the majority of States, that a noncustodial parent who receives Social Security disability income benefits is entitled to modification of his child support obligation. See Rosenberg v. Merida, 428 Mass. 182, 185-186 (1998). See generally Annot., 34 A.L.R. 5th 447, 469-[452]*452487, 498-503 (1995). We have also decided to treat Social Security retirement benefits the same as disability income benefits. See Rosenberg v. Merida, supra at 186 n.4. See also Cohen v. Murphy, 368 Mass. 144, 147 (1975). We agree with the conclusion reached by the judge in this case that the same logic should extend to Social Security death benefits. Survivor’s benefits are to be used for the beneficiary’s “current maintenance,” which includes the “cost incurred in obtaining of food, shelter, clothing, medical care, and personal comfort items.” 20 C.F.R. § 404.2040 (a)(1), (c) (2000). The benefits are designed to replace a deceased parent’s income that would otherwise be available for the child’s current maintenance. Those benefits, now totaling $927 a month, as of January 1, 1991, must be considered a credit to the father’s estate in determining child support obligations. See Brewer v. Brewer, 244 Neb. 731, 740 (1993), and cases cited. See generally Annot., 34 A.L.R. 5th 447, 507-513 (1995). The child support order must be modified to reflect this credit.
The question whether a judge may posthumously “set aside a lump sum in trust as security for future educational support” for the child is a more difficult one. The Legislature has explicitly provided that in some circumstances parents have an obligation to provide educational support for children who have attained the age of eighteen: “The court may make appropriate orders of maintenance, support and education for any child who has attained age eighteen but who has not attained age twenty-one, who is domiciled in the home of a parent and is principally dependent upon said parent for maintenance” (emphasis added). G. L. c. 209C, § 9. As a general rule, support orders regarding the future payment of “post-high school educational costs are premature and should not be made.” Passemato v. Passemato, 427 Mass. 52, 54 (1998). We have, however, upheld an order creating an educational trust for a minor child who is neither about to attend nor already enrolled in higher education; those cases must be “based on the particular facts” of the case. Id. See Bush v. Bush, 402 Mass. 406, 410 (1988) (child support orders should reflect “current needs” of child).
The judge here appropriately recognized that an order for postminority support for a young child would generally be premature, but relied on our decision in Passemato v. Passe-mato, supra, to conclude that the “circumstances of posthumous support” was a valid exception to the general rule because [453] “[k]eeping the estate administration open for a decade or more poses significant problems and expense.” We share the judge’s concern that children bom out of wedlock (or whose parents are divorced) and who suffer the death of a parent before they reach majority should not be deprived of access to parental support for their educational needs when they reach the age of eighteen. On the other hand, the Legislature plainly contemplated that a child seeking such support had to “attain age eighteen” before doing so. Additionally, the statute provides that at age of eighteen a child may be entitled to such support only if “domiciled in the home of a parent” and “dependent upon said parent for maintenance.” G. L. c. 209C, § 9. These contingencies make plain the Legislature’s desire that awards for educational support be reserved for those cases where an award would meet the current needs of the child. To allow a judge to secure funds in trust for a child’s future education at a time when the judge cannot foresee whether the award will be warranted under the statute and where, because of death, the parent cannot later challenge the validity of the use of funds held “in trust” for educational needs is beyond what the Legislature may have intended. In that respect this case differs from our holding in Passemato v. Passemato, supra, where, presumably, the mother could later challenge the expenditure of specific funds set aside for the future educational needs of her children.
The Legislature has increased significantly the obligations of parents to support their children, imposing an obligation to provide support for their children’s educational needs after the age of eighteen. Because the statute places limitations on educational support awards and does not limit general support awards for children under the age of eighteen in the same way, we conclude that the establishment of an educational tmst fund while the child is ten years old and where there can be no showing that she presently meets the statutory requirements of G. L. c. 209C, § 9, is not authorized in this case.27 Our opinion is bolstered by the public policy that a testator should be free to dispense with his estate as he sees fit. G. L. c. 191, § 1. See Damon v. Damon, 312 Mass. 268, 271 (1942) (“a testator has a right to dispose of his own property with such restrictions and limitations not repugnant to law as he sees fit”). While we have already explained that this interest is not always paramount, [454] absent a more clear expression from the Legislature we think a judge in the Probate Court lacks the authority to order future educational support to a child who has not yet attained the age of eighteen, because of the death of her father.
5. Answers to reported questions. We conclude that the judge’s questions, as reported, must be answered as follows: (1) a testator survived by a minor child may disinherit that child, pursuant to G. L. c. 191, § 20, subject to the prior satisfaction of all of his child support obligations, present and future; (2) a minor child’s claim for support is in the nature of a preferred creditor’s claim and must be satisfied prior to any testamentary dispositions; (3) assets in an inter vivos trust containing the terms of the trust at issue here (see note 7, supra) can be reached to satisfy support obligations; and (4) a judge in the Probate and Family Court does not have the authority to enter an order after the death of the obligor to secure postminority educational support for a child who does not presently qualify for such support pursuant to G. L. c. 209C, § 9.
So ordered.