Should the grandfather's will, which stipulates the inheritance of males to the exclusion of females, be executed in the absence of a will from the father?

A will that deprives females of inheritance is forbidden and unjust, as it violates the boundaries set by Allah Almighty. It is not permissible for the heirs to act upon it; rather, women must be given their rightful share. A will in favor of an heir, whether male or female, is not permissible unless the other heirs agree to it. If the deceased did not make a will, then the estate must be divided according to Islamic law, and everyone entitled to a share must receive it.