Can anyone help my dad is hunsted by demons?

First off my nephew died i the house two years ago. so there bad memories in the house to start off. now my step mom and half sister wont even talk to him. now about him and the demons...they sit at the end of his bed staring at him they are constantly taking his blanket from him through out the Night. he has placed a cross at his headboard to ward them off while he tries to sleep which has been unsuccessful..he had one event where he had got turned around in his bed and was being suffocated he managed to break loose. I am worried about him and looking to find some advice or help for him.