What should a wife do whose husband is molesting their daughter, and has stopped being intimate with her, and she fears for her daughter?

The father's molestation of his daughter is an abominable and forbidden act. The mother must advise her husband and instill in him the fear of Allah so that he may cease his disgraceful action. If he repents, that is what is desired, along with monitoring him to ensure the sincerity of his repentance. If he does not repent, the daughter is not permitted to remain in the home; she must depart to a safe place with one of her mahram relatives, while concealing her father's actions, unless it is possible to seek help from a wise and influential relative to advise him. This separation should continue until the father repents or the daughter gets married.