This is an unofficial version of a Massachusetts General Law.
Section 2-711
If an applicable statute or a governing instrument calls for a future distribution to or creates a future interest in a designated individual's “heirs”, “heirs at law”, “next of kin”, “relatives”, or “family”, or language of similar import, the property passes to those persons, including the commonwealth under section 2-105, and in such shares as would succeed to the designated individual's intestate estate under the intestate succession law of the designated individual's domicile if the designated individual died when the donative disposition is to take effect in possession or enjoyment. If the designated individual's surviving spouse is living but is remarried at the time the interest is to take effect in possession or enjoyment, the surviving spouse is not an heir of the designated individual.