Is the paper written by the deceased, indicating his sale of his share of his father's house to his brother, considered a binding sales contract that allows the brother to take possession of this share, or is it considered a will that does not permit him to do so?

If a person dies and leaves behind only two full brothers and two full sisters, then their inheritance is divided among them by 'asabah (agnatic succession), with the male receiving the share of two females, in accordance with the Almighty’s saying: "And if there are brothers [and sisters], both men and women, then the male will have the share of two females." The inheritance is divided into six shares: each brother receives two shares, and each sister receives one share.

As for the document claiming that the deceased sold a share to his brother, as long as the brother was not aware of the contract, the sale did not take place due to the absence of the conditions of offer, acceptance, and consent. And if the deceased intended it as a bequest to his brother, then a bequest to an heir is forbidden by Islamic law and is not enforced except with the consent of the other heirs. Therefore, the brother has no right to this share; it is to be divided among all the heirs according to the lawful Islamic division of inheritance.