What is the ruling on the money that the maternal grandmother gave to her mother in exchange for supporting her, and is it permissible to inherit this money and the house built with it? Did the grandmother sin by giving away all that she owned? Is it permissible to live in this house? Is it possible to give the mother a monthly rent for living in it to clear one's conscience?

The preponderant opinion is that grandchildren are not like direct children in terms of equal distribution in gifts. Therefore, there is no objection to the grandmother singling out her granddaughter with a gift, even if she has other children or grandchildren. The gift is valid if the grandmother stipulates that she be provided for until her death. There is no objection to the questioner's mother accepting the gift, and no sin upon the grandmother. There is no harm for the questioner to reside in the house. The mother must pay zakat on her wealth, but usurious gains are not subject to zakat and must be disposed of.