Is the debt on the mother if she already owns the house, or on the father? And is the father's purchase of the car considered a gift if the illness of death played no role in his decision, and what does it mean to place a ban on a patient with the illness of death, and is it permissible for the mother to buy the car for the sister from the father's money, and is it obligatory to inform the siblings of my relinquishment of my right to the gift?

The aforementioned debt is incumbent upon the father and must be settled from his assets, for the Prophet, peace and blessings be upon him, said: "The soul of the son of Adam remains suspended by his debt until it is paid off on his behalf."

The previous fatwa does not change with the father's decision to buy the car before the onset of the illness, because he became interdicted from the moment he contracted the mentioned illness. His intention is not considered valid as long as the execution took place after contracting the illness. The interdiction of a sick person prevents him from disposing of his wealth in excess of one-third, except for medicine and sustenance. Those who interdict the sick person are all of his heirs.

Accordingly, the mother is not responsible for the father's money, and she is not permitted to buy the car for the sister from the father's money. The questioner should inform the rest of the heirs of their right to the car, and inform the sister as a form of advice.