How can one deal with a mother who frequently slanders her son's wife, knowing that the wife has been patient for five years and has now reached the point of seeking divorce, while also considering the husband's fear of displeasing his mother?

You should not resort to divorce when any problem arises; rather, you must strive to solve it. You should try to appease your wife and reconcile her with your mother, convincing each of them of the necessity of coexisting and treating the other with the manners of Islam. Alert your mother to the impermissibility of backbiting and harm. If the problem persists, house your wife in a separate dwelling. Urge your wife to be patient and to respond to ill-treatment with kindness. If these solutions are not effective and you fear that the matter will lead to undesirable consequences, then there is no objection to divorcing her if she requests it to remove harm, knowing that it is not obligatory to obey your mother in divorcing your wife.