What is the ruling of Islamic law regarding not divorcing one's wife based on the father's request, given that the husband does not wish to divorce her due to her illness and lack of livelihood, and that not divorcing her may lead to the father's anger and estrangement from his son?

It is permissible for a husband to strike his wife a non-painful blow if he fears her disobedience (nushuz) and if admonition and abandonment have not been effective. The questioner should reform his wife through admonition, patience, and by encouraging her to be gentle with his father. If she becomes upright, he should keep her, and his father does not have the right to insist on their separation. However, if she does not abandon her stubbornness and he despairs of convincing her, then it is better to leave her to please his father and for his own peace of mind. Filial piety is an obligation that nothing can waive.