S.M.
Hi, I agree with all these... usually tonsils and adnoids, and drs will remove them if they feel they are large enough to interfere with sleep. Some may recommend a sleep study first, which isn't a half-bad idea, but most will send you straight to the ENT. See if it improves once all the cold symptoms are gone, and then decide if you think it could be causing him to not get a good nights sleep.