Is it permissible for a father to compel his daughter to waive her right to inheritance—during his lifetime—in exchange for receiving a small sum of money from her brothers?

"A sister is not entitled to demand her share of her parents' inheritance while they are still alive, as inheritance pertains to the deceased. It is permissible for the father to distribute his wealth as a gift during his lifetime, but it is better not to do so due to the possibility of him needing it. What the brothers did by paying their sister money in exchange for her share of the house is not valid unless the father had divided the house and assigned each individual their share, or if she sold her undivided share specifying the proportion. However, if she sold her share without specifying the proportion, or relinquished what would accrue to her in the future without the father assigning ownership, then the sale is not valid due to the uncertainty of the sold item and the inheritance not being confirmed except after death. In this case, the money becomes a debt owed by the sister, and the father can rectify the situation by assigning her ownership of her share for her to sell it to them, and then conducting a set-off between the debt and the price."