Is it permissible for the sister's brothers to demand their right from the house that the father registered to a son and a daughter, then the son sold his share to his sister, and then the sister sold the entire house?

It is not permissible for a father to favor some of his children over others in gifts and endowments unless there is a legitimate Sharia justification for it. If he does so, his will is invalid. If a father gifts his house to some of his children during his lifetime without fairness among all his children, then the gift is invalid, and the house remains an inheritance to be divided among all heirs according to Sharia. If the father intended for the children to take the house after his death, this is a bequest to an heir, which is not enforceable without the consent of the remaining heirs, based on the Prophet Muhammad's (peace be upon him) saying: "Indeed, Allah has given every rightful person his right, so there is no bequest to an heir." If they do not consent, they have the right to demand their rightful share. The children who benefited from this unjust gift should fear Allah Almighty and know that their father’s action is legally invalid according to Sharia.