Is it permissible for a mother to transfer her share of a house to her daughter, while reserving the right to dispose of it after her death, knowing that part of the money used to purchase this house was inherited from the father, and the deceased brother has a share in it, and the mother has siblings?

A written document intended to transfer ownership of real estate after the owner's death is a will. A will in favor of an heir is forbidden by Islamic law, based on the Prophet's (peace be upon him) saying: "Indeed, Allah has given every rightful person his right, so there is no will for an heir." However, this forbidden will becomes valid and contingent upon the approval of the heirs, as the Prophet (peace be upon him) said: "There is no will for an heir unless the heirs wish it." Therefore, your mother cannot bequeath to you her share of the house if she has other heirs besides you.