My friend has a demon at her bedroom window since she was seven.?

Shes now 16 and the demon has never gone away except sometimes in the morning. He just stays at her window the whole time Looking at her and at the inside of the room. I was thinking that i should attempt an astral projection and Approach this demon/Evil entity. How do we get rid of him? Why can she see him when shes not even in her astral body?