What is the ruling of Islamic law regarding a grandmother registering a house she bought with her own money in her daughter's name, and what must the daughter do after her mother's death, given her intention to sell the house?

If the grandmother sold what she inherited and bought a house, registering it in the aunt's name as a gift after she was afflicted with dementia, then the action is void and must be annulled, and the matter can be taken to court. However, if her action was while she was in full possession of her mental faculties, then there is a detailed explanation:

1. If she did not hand over the house to the aunt: The gift becomes void upon the grandmother's death, and the aunt has no right to it. 2. If she handed over the house to the aunt and she disposed of it as an owner would: In the case of her good health: If she had no other children besides the aunt: The gift is valid. If she had other children: The gift is not valid unless she gifted to her other children a similar amount to what she gifted to the aunt, or if the other children waived their right to equal treatment. In the case of death illness: It is considered a will to an heir, and it is not enforceable unless the rest of the adult, mature heirs agree, due to the Prophet (peace be upon him) saying: "Indeed, Allah has given every possessor of a right his right, so there is no will for an heir." And in another narration: "Unless the heirs permit it."