When my child was having nightmares and seeing demons also it was from a children's movie that actually had real voo-doo in it that came from a book.
So once we got rid of it and I prayed over her and In Jesus name I told everything that was invited in with that item to leave. Also I had to bind up and not allow night terror, witchcraft, and all familiar spirits over her in Jesus name.
The nightmares left when we did figure it out and got rid of the item.
It's about what's in the children's books and what it invites. So we don't keep books with occult stuff, such as dragons, spells and curses in our house, or the toys that go with them. We can't have stuff that is linked up to false religions or false gods either. Some may not understand this and say this is crazy but once you have seen the evil spirits come because of these items and then leave in Jesus name you can't help but to know it's true.
God doesn't want us to give the devil any door to come into. God leaves us responsible for protect our kids from these type of attacks. Yes a lot of children's stuff it contaminated with the above listed stuff plus even more. Thank God there are still many good choices, and materials suitable and safe for kids and us!
Behold, I send you forth as sheep in the midst of wolves: be ye therefore wise as serpents, and harmless as doves. Matt 10:16
Beloved, believe not every spirit, but try the spirits whether they are of God: because many false prophets are gone out into the world.1 John 4:1
My people perish from a lack of knowledge.> Hos 4:6
There are many videos on youtube exposing the occult in cartoons and disney stuff.Also I have many deliverance prayers and such to help with spiritual warfare that could help also.https://hubpages.com/@heavenbound5511