What is the ruling of Islamic law regarding a mother who disposes of her wealth in favor of her daughter's son, in order to disinherit her own son with whom she has a dispute, and to disinherit her daughters' husbands from inheritance, knowing that she has one son and two daughters, one of whom has no children and the other is the mother of that son and has other children?

A child must be dutiful to their parents, especially the mother. The husbands of daughters are not heirs to their wives’ mothers. A person is permitted to dispose of their property through a gift or charity if it is immediately effective. However, if it is contingent upon the death of the giver, it then takes the ruling of a will, and thus is not permissible for an heir, nor for more than one-third, unless the heirs approve. It is not permissible to dispose of property with the intention of depriving heirs of their right, and whoever does so will be treated with the opposite of their intention. Therefore, what this mother is doing, giving her property to her daughter's son, is not permissible if it is intended to deprive her heirs.