Is it permissible for a son to pay his deceased mother's deferred Mahr (dowry) on behalf of his deceased father, and would the father's obligation be absolved merely by the son's pledge to do so? What are the best and most rewarding ways to dispose of the mother's Mahr for her?

The deferred dowry is a debt owed by the deceased, to be taken from their estate before its distribution among the heirs. Scholars have differed on two opinions regarding the absolution of the deceased's liability for their debt through a guarantor. Most of them hold that it is not absolved except by repayment, and not merely by a guarantee, based on the hadith: "The soul of a believer is tied to his debt until it is paid off," and the hadith of Abu Qatadah when he paid off the debt of the deceased, whereupon the Prophet - peace and blessings be upon him - said to him: "Now his skin has cooled."

This deferred dowry is a right of the mother and is considered part of her estate, to be divided among her living heirs on the day of her death. If the mother dies before the father, the father inherits one-fourth of the dowry, based on the words of Allah Almighty: "But if they have a child, then for you is one fourth of what they leave after any bequest they [may have] made or debt."

The mother's dowry is a right of her heirs, and it is not permissible to dispose of it through charity or otherwise except with the consent of all adult, discerning heirs.