Is a mother sinful for asking her son to divorce his foreign, non-Muslim wife, who refuses to convert to Islam, given the affection between the spouses and their daughter?

If the mother requests her son's divorce from his wife for a legitimate Islamic reason, such as the wife being non-Muslim and out of fear for the children, then there is no sin upon the mother, and obeying her in this matter is obligatory. However, if the mother perceives that her son is attached to his wife, it is better for her not to ask him to do so. But if the wife is not from the People of the Book and marrying her is impermissible, then the husband must separate from her, and the mother should command him to do so.