First, Thank you for asking this question and for considering what the little boy needs for security. I would ask him specifically what he needs to feel safe. I would encourage you to lay down with him and help him get to sleep, and then slowly or gradually move out of the room. Start in the bed, then sit beside the bed, hold his hand, ask him if he feels like having a "super hero" or a specific stuffed animal in the bed would work. Encourage him, talk to him about what he needs. Even ask him what his fears are and make him understand why these things are untrue. Debunk his faulty or fearful thinking. the most important thing, is finding out what makes him feel safe and letting him determine what would help in the room or his own bed. Trauma affects kids differently. But as a trauma specialist, I have found that you have to focus on what the fearful thoughts are, finding out where they came from, and then focus on how he can understand that these are not true. Point out exceptions to him how that problem no longer exists.
I hope that is helpful. I have two little ones also, and I think a lot of parents deal with this issue, but it can and will get better :)
I hope that you found the time to review my answer and that you will provide positive feedback. If more information is necessary, please feel free to respond. If you do feel satisfied, please accept the answer so that credit is received for the response. Thank you so much! Julie