Is it permissible to deduct the amounts that a father paid to his children (such as aid for marriage or educational expenses) from their shares of the inheritance?

The answer summarizes the rulings concerning money paid by a father to his children as follows:

Firstly: Money paid by the father with the intention of it being a loan (for expenses not obligatory upon him) must be returned to the inheritance after his death.

Secondly: Money paid by the father for the marriage of one of his children with the intention of it being a debt entitles the father or his heirs to demand its repayment.

Thirdly: Gifts that are not obligatory expenses, if a father singles out some of his children with them, the majority of scholars hold that these gifts become effective upon his death. However, others (such as Ibn Taymiyyah) believe that the singled-out child must return what he was favored with to the inheritance.

Fourthly: If a father helps one of his children who needs money for marriage without the intention of it being a loan, there is no harm in that, and it is not considered a violation of justice; because it is a gift given due to a need, and the child is not required to return it.

Fifthly: If one of the children needs to get married, it is an act of justice for the father to assist him, just as he assisted those before him.

Sixthly: Expenses for children's education are not obligatory upon the father, and whatever he spends on it is considered a gift given due to a need, which the father is permitted to give.