I'd suggest checking him for Tourette's also.
There are some disorders (neurological I think) that can cause this. Torrettes Syndrome is one off the top of my head. I actually have a very dear friend who's 11 year old has this, and it is well controlled through medication. If I didn't know he had it, I wouldn't know. Not saying that is what it is, just a possibility. You should have him seen by his Dr. who can order appropriate tests. Don't be afraid..as far as I know none of these things are life threatening or anything, and can be well controlled through medication. I'm sure he will do fine once they sort out what it is exactly. All the best to you.