What should I do about my ex-wife who prevents me from educating my daughter and instills hatred for my family in the hearts of my children, knowing that I bear their expenses? Should I resort to court to obtain their custody, even though I do not wish to separate them from their mother at this age?

Both parents have the right to visit their children if custody is with the other parent. The one who has custody is not permitted to prevent visitation, provided that there is no private seclusion (khalwa), excessive length, or inappropriate casualness that violates Islamic manners. The father may look after his child, discipline him, and educate him, but the children should only spend the night with their mother. If the mother refuses this, the matter can be taken to court.