Is it permissible for the only daughter to dispose of her sick mother's money, which the mother obtained from selling her own land, given that the mother has gifted the apartment to the daughter and relies on her for care, and that the mother has living sisters and children of deceased brothers?

If a mother grants an apartment to her son during her lifetime, while she is of sound mind, and the son takes possession and seizes it, then the grant is valid and effective. As for the money from the land, it belongs to the mother as long as she is alive, and it should be spent on her expenses and needs. Whatever remains of it after her death belongs to the heirs. The son is not obliged to spend on her from his private wealth as long as she possesses what suffices her.