Is it permissible for a father who has irrevocably divorced his wife to live with her in the same house, while refusing to rent a separate apartment despite being able to do so? And is it permissible for the son to withhold financial support from his father to pressure him into accepting the separation?

If the apartment is spacious and has separate facilities for both the divorced man and his ex-wife, then it is permissible for them to live together in it; otherwise, it is not permissible. If the facilities are shared, then the one who does not own the apartment must secure independent housing for themselves. It is not permissible to cut off maintenance for the father with the intention of pressuring him; rather, one must honor him, treat him kindly, and advise him gently.