Hi Malisa,
This might be a stretch, but evaluate his breathing and see if he clenches or grinds his teeth when he is sleeping or if he has his mouth open when he sleeps. Does he have a narrow arch form? If any of these, you might want to have his airways evaluated by a Neuromuscular Dentist http://top3dentists.com/pages/neuro_dentistry and also their pediatrician together. I hope this helps
While his pediatrician should be able to address your concerns, if you'd prefer, it wouldn't hurt to consult with a pediatric neurologist about his repetitive motions. It may be helpful to record on your cell phone or camcorder a little bit of the activity for the doctor to see. I don't know much about repetitive motions in children when going to sleep, just read about it. I have a repetitive movement disorder of sleep, which is not the same thing. Best wishes.