I think it's selfish for you to let the boy suffer due to your own unfortunate health problems, and irrational fears. Tonsils do NOT protect you from diabetes. Not all diabetics have a family history, and besides there's reccessive genes.
My daily suffering is only experienced by me. No one understand how it is, and the boy should be made as comfortable and happy as possible. People write you off as a hypocondriac after a while, and don't want to hear it. This has been my experience so I often suffer in silence because no one cares.
I had my adenoids out six years ago, and can actually breathe now. For eight years, I couldn't breathe through my nose easily or smell anything. I have nasal polyps which make it worse. Your son sounds like he has polyps. They should be removed, but they do come back. You either have this affliction or not.