Are children sinful for responding to their mentally or psychologically ill father, who gratuitously insults them and refuses treatment, with exasperation? And is the mother sinful for abandoning her marital bed for the same reason?

Filial piety is among the greatest acts of devotion, and disobedience to parents is among the greatest prohibitions. It is not permissible to raise one's voice at them or to rebuke them. Allah Almighty said: "So do not say to them, 'uff,' and do not repel them but speak to them a noble word" and "But if they endeavor to make you associate with Me that of which you have no knowledge, do not obey them but accompany them in [this] world with appropriate kindness." Since the father is mentally ill, it is even more imperative to treat him gently, show him kindness, be patient with him, and dedicate oneself to his treatment. As for the wife, it is not permissible for her to abandon him, leave his bed, or mistreat him. If he is harming her and she cannot bear it, she may request a divorce, but it is better for her to be patient.