What is the ruling on stipulating the cancellation of the deferred mahr in the marriage contract upon the husband's death, after agreement with the family and the wife?

This condition in the contract is not binding, because it is not permissible for a woman to waive any part of her dowry before it becomes due. Rather, it is permissible to waive it only after the dowry has become a confirmed debt owed by the husband. Therefore, this is merely a promise from the woman to waive the deferred dowry upon death. If the contract is concluded, the woman has the right to retract her promise or to fulfill it.