How very kind of you to respond so quickly - I'll call his mom tomorrow and suggest the tent. She does have a night light for him but he seems to need more comfort - he has been asking for his father to sleep with him. I did read recently that his sensory problems may create an insecurity and that he may not feel grounded enough and that covering him with heavy blankets; or a "weighted vest"; or perhaps tucking him in very tightly may help. Also, he may be afraid of falling off the bed - I was going to suggest that they lower his bed - what do you think?My nephew who is three (recently diagnosed as mildly autistic) sleeps with the blankets over his head, says that he is frightened; of course he gets extremely hot in the night, which disturbs his sleep- any suggestions.
Maybe some sort of bed tent, so the blankets don't have to be right on top of him?
Or a nightlight or lamp so he doesn't feel frightened?
I agree that the problem could be sensory in nature. You can have the family try completing this sensory questionnaire. It should help them identify which senses are problematic for him. The weighted blanket provides deep muscle pressure that is soothing for the "proprioceptive" sense.
http://www.sensory-processing-disorder.com/sensory-processin g-disorder-checklist.html
Here's an article about sleep from the National Autistic Society in the UK (they always have such good advice about stuff).
http://www.nas.org.uk/nas/jsp/polopoly.jsp?d=1071&a=3376
Good luck with everything.
Ali does the same. She has recently said (due to my telling her it is not good to keep the blankets over her head cause it makes it harder to breathe) that it is her "clubhouse".
Two things to try --- perhaps he'd enjoy sleeping in a sleeping bag, it might satisfy the cacoon feeling he is looking for. Also, I know a little guy that has bunk beds -- he sleeps in the bottom bunk and his parents hang a sheet from the top bunk and make a "fort" for him. He loves sleeping in his "cave".
Both of my kids (one ASD and one NT) wanted to sleep with the covers over their heads. So, we compromised. I gave them each a thin receiving blanket and told them it was their "cozy night night" and they would put that over their heads. Since it was so light, they weren't hot and they both still sleep with them.