All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger. We ask Allaah to exalt his mention as well as that of his family and all his companions.
First, we ask Allaah to facilitate your affairs, to make a way out of your distress and hardship, and to reconcile your parents. We advise you to be wise in dealing with this matter of separation between your parents. You have to endeavour to reconcile between them, as this is one of the best acts of being dutiful to them. Allaah says (which means): {…and the settlement is best;…}[4:128]. The first means for reconciliation is to seek the help of Allaah and invoke Him earnestly to soften their hearts and reconcile between them. Besides, you should behave with them in a good manner as, by doing so, you could influence them and win their affection. There is no harm in seeking the help of your relatives who are pious and righteous in order to reconcile between them. If your parents reconcile, then that is what is required, if not, at least they should be convinced, especially your mother, not to prevent you [or any of your brothers and sisters if any] from seeing the other parent. However, if one of your parents prevents you from seeing the other one, then you do not have to obey them in this issue as there should be no obedience to a creature if such an obedience constitutes disobedience to Allaah. The Prophet said: "Obedience is limited to good and righteous matters." [Al-Bukhari and Muslim]
Finally, we remind you that it is an obligation on you to be kind to your mother even if she mistreats you or your father.
Allaah knows best.