What is the ruling of Islamic law regarding a wife who constantly demands divorce from her husband, does not adhere to the teachings of the religion, and whose family desires her divorce, knowing that the husband fears for his children from the upbringing of this wife and her family?

A husband should divorce his wife if she abandons prayer and is abusive in her conduct, due to her negligence in fulfilling the rights of Allah. Ibn Taymiyyah held that divorce is obligatory in this situation. If he divorces her, the mother has a greater right to custody, unless she is immoral, in which case the father has the right to bring the matter before the judiciary to invalidate her right to custody. He should also perform Istikhara (prayer for guidance) and supplicate to Allah.