What is the ruling of the Sharia on a wife who daily insults and slanders her husband's mother, and what should the husband do towards her, given his disapproval of her actions and the presence of children between them?

A wife who curses her husband's mother and mistreats her, insulting her, commits a great sin and a grave transgression. This is because cursing a Muslim is فسوق (disobedience/impiety), and insulting them is evil, especially if the abuse is directed at the mother of the husband, whose obedience Allah has made obligatory. Abusing the mother is also an abuse of her son. She must repent and apologize to her husband's mother and to her husband. Allah Almighty has called this a clear abomination. If she does not stop cursing and slandering, the husband must deter and rebuke her, even if through abandonment (هجر) or light, non-injurious beating, because this is part of his qawamah (guardianship/headship) to preserve the mother's status. If the matter does not cease, he should separate each of them by place.