Is it obligatory to carry out a mother's will to disinherit her eldest son on the pretext that he has taken his share, and when should the inheritance be divided if there are minor children and the adult children demand immediate division?

This will, which disinherits the eldest son, is neither permissible nor valid, as it transgresses the limits set by Allah and harms one of the heirs. Allah Almighty says: (from after any legacy [left by will] or debt, without causing harm). And a mother marrying off her son is a righteous deed, and she is not obliged to give the rest of his siblings the equivalent of the money she spent. The inheritance must be divided among all heirs, with each taking their lawful share from it. As for some heirs demanding the division of the inheritance, this is their right, and their request must be granted. As for the minors, their money should be preserved for them and spent on them from it. When they reach maturity and are of sound judgment, they should be given what remains of their money.