How should one deal with a father who molested his daughter and fathered a child with her, knowing that he refuses discussion, threatens, cites displeasure, and does not fulfill his paternal or religious duties?

There is no obedience to the mother in her command to abandon the father and not to confront him. Rather, he must be prevented from forbidden acts. The daughter must not obey him, and she must deter him to the best of her ability. The mother must prevent him from these acts, and she is permitted to seek a divorce from him. Some scholars consider her forbidden to him due to his fornication with her daughter. It is not permissible to remain silent about this evil; rather, it must be changed by whatever means possible, even by referring the matter to the authorities. The daughter is not permitted to be alone with her father if he has not repented.