Yes, I have spent countless conversations asking him how things are going, how school is going, is there anything bothering you, is there anything you would like to talk to me about...Telling him "you know you can tell me anything and it will stay between the two of us", and he has not said anything..All he says is that he is scared that someone is going to come in his window and get him.
Well, I don't think you have to worry about him being 21 and still doing this.
The reason I asked about tramatic events is because knowing what is really going on with him IS your solution. I would bet anything he is feeling insecure. This is the behaviour of an insecure child, at least as far as I am concerned. I have no doubt the scary movie didn't help matters, but I would bet there is more then that going on with him. You mentioned that you talked to him about the movie not being real, and about your own fear when you were a child. Has anyone actually asked him why he is upset or worried? I might not address it as why he is afraid to sleep alone, that might make him feel ashamed and that certainly would not help his sense of security. I would just ask him if there is anything bothering him, or that he is worried about. Sort of more in general terms. I do think if you can get to the root of what is making him feel so insecure, you will be able to resolve the issue. You might also try this question on the expert forum. Here all you get are opinions, and those of course are based on our own experiences (which is what my opinion is based on). Might not hurt to give it a try.
If there has been any sort of traumatic incident, neither myself nor either parents know anything about it. He confides in anything that goes on in his life. He stays on a regular schedule as far as the commute between his mother's house and our house. My husband and his mother do not speak unkindly to one another in his presence, and I know my husband does not speak negatively about his mother in front of him. As far as what his mother says about his father when he is with her, I have no idea. My thing is, what should be done about this? He is too old for either of us to sleep in there with him, and he keeps us up at night crying and coming to our room waking us. The movie was about a man that kidnapped people and tortured them, so I know that, had he not watched this, he would probably be over it. I have tried to tell him that he has to learn to stay in his room all night and he will see that nothing is going to hurt him. That is the only way to truly move past this. He has to do this on his own, since we watched a movie that he knows that he is not allowed to watch. I did the same thing when I was younger, and my parents made me stay in my room and conquer the problem myself. I sure hope it will pass, because I do not want him to be 21 years old and still afraid to sleep by himself...
I had this problem as a kid. I had a very active imagination and was a very sensitive kid. I remember pulling the comforter right up to my chin as I convinced myself then nothing could "get me". It was a protective thing. I believe this stemmed from huge insecurities. My parents had a very bad marriage and my dad was back and forth in our home. I was a super insecure kid, and that translated into a fear of sleeping in my room alone. So I wonder..has there been anything traumatic or stressful in this kids life recently? Anything making him feel insecure? It may be something that seems insignificant to an adult, but can be a big deal with a kid. Is he back and forth between this house and moms on a regular basis? Do either parent speak badly about the other, or do they fight in front of him? Or maybe something at school such as a bully?
Also, I have no doubt the scary movie made things worse.
It could also just be a phase and time is all that's needed. He is only 10...I don't think that's too old. Something may have just spooked him and over time it will pass.