What is the ruling on filing for divorce from a wife who called her husband "son of a fornicating woman," knowing his mother's righteousness and adherence to her religion, and his desire not to be separated from his son?

In such cases, reconciliation or resorting to Sharia courts is preferable. The role of fatwa (religious edict) is guidance and direction. If the wife insults her husband with the worst insults, such as calling him "son of an adulteress," this is an injustice, a rebellion (nushuz), and an accusation of adultery against his mother. Accusing someone of adultery (qadhf) is one of the gravest sins. Do not rush to divorce; instead, advise her, remind her of God, and encourage her to repent. If she does not repent, then seriously consider divorcing her. If you divorce her, she has no right to custody if her immorality is proven due to the insults and accusations of adultery, and custody transfers to the most eligible among the females. It should be noted that even if custody is forfeited, the right to see the child remains.