Is it permissible for me to work with my father in his wealth, in which he uses usurious banks, especially since he is not convinced of its prohibition, suffers from many illnesses, and has caused me suffering in the past?

It is advised to be patient in the face of tribulation, to pray for the guidance of one's parents, and to treat them kindly no matter how much they mistreat you. It is permissible to work with your father if the work is in permissible fields and does not involve directly assisting him in consuming usury, as what is forbidden is assisting in sin; for Allah Almighty says: "And do not cooperate in sin and aggression." Dealing with someone who consumes usury is not absolutely forbidden, as the Prophet, peace and blessings be upon him, used to deal with the Jews even though they consumed illicit gain and took usury.