Is it permissible for a woman to وقف (endow) her house for the poor after her death, and to purchase her father's share from her siblings to وقف (endow) it for her mother and father, so that her poor brother may benefit from its rent? And is it permissible for her not to bequeath to her siblings?

Attaching an endowment (waqf) to death is valid according to the majority of scholars, and it takes the ruling of a bequest (wasiyyah). Thus, it is executed within the limits of one-third of the estate if the beneficiary is not an heir. What exceeds that, or if the beneficiary is an heir, it is not executed except with the consent of the heirs. Therefore, if the poor brother is an heir, the execution of the endowment depends on the consent of the remaining heirs; otherwise, they have the right to their legal share of the house. As for endowing the house for the poor, if its value does not exceed one-third of the estate, it is valid. If it exceeds that, the execution of the excess depends on the approval of the heirs.