I would ask him if the other hand ever feels like that or his feet. Also whether if it stays that way or if it's like that when he wakes up (like it fell asleep from sleeping on it, etc).

Of course, it's Saturday now (I just saw the post) so don't know if you call the doctor or not, but Tuesday is right around the corner....and of course it should be mentioned then.

Let us know what they say.