How is the estate of a husband who has no heirs divided? Does it all return to his wife's heirs (the 'Asabah) according to his will?

A woman's will concerning charitable acts is valid and is paid from her estate, with the remainder divided among her heirs. As for a husband's will bequeathing all his wealth to his wife in the absence of other heirs, it is permissible according to many scholars, subject to its conditions. However, in this case, it became void due to the wife's death before the husband. Consequently, the wife's 'asabah (agnate relatives) have no right to his estate. When a will becomes void, the inheritance reverts to the Muslim treasury (Bayt al-Mal) if it is well-regulated; otherwise, the Muslim community should spend it on general Muslim welfare and charitable endeavors.