i agree with all the suggestions here,sister, but i would ad, pray before you sleep that god would give you peaceful dreams. Sometimes its spiritual but other times its an over active mind. I suggest you prepare before you go to sleep by reading or watching positive things, wether scriptural or fiction. Literally tire your mind, letting the last thoughts before you drop of to sleep, be of a positive nature.
Father God, i pray that you take control of my sisters thoughts during her sleep. If there is anything she needs to learn from the dreams she has had up to now, make that clear to her. If there is nothing beneficial in her dreams i pray that you will renew her mind, releasing her from any fears and replacing them with your peace. Lord, if there is attack from the enemy here, i ask that you break any hold that he has over your child, he has no rights over her, and in Jesus name i command him to leave her in peace. We have authority over you Satan, from what Jesus has done for us on the cross and i claim that right, In Jesus name,, Amen