Is it permissible for an aunt to bequeath half of her dwelling to her nephew while she has a brother, and does this gift contradict Sharia or inheritance laws?

A gift (hiba) is what a person gives to another during their lifetime. For it to be valid, it is stipulated that the donor must be in good health and of sound mind, and the donee must take possession of it before the donor's death or bankruptcy. So, if the paternal aunt gifted half of the dwelling while she was healthy and of sound mind, and the donee took possession of it, then it belongs to him, and the heirs have no right to it. This is based on the statement of Ibn Abi Zayd: "Neither a gift, nor a charity (sadaqah (definition)), nor an endowment (habs) is complete except by possession (hiyaza)." This is further supported by what Malik reported in Al-Muwatta from Abu Bakr, may Allah be pleased with him, who gave Aisha, may Allah be pleased with her, a gift that she did not take possession of. He said to her: "Had you harvested it and taken possession of it, it would have been yours, but today it is the property of the heirs."