Does it open up the tubes or just pressure your ears up so that you are more comfortable at depth?Its legit. You just put water in your mouth, get rid of the air in there, stick it in your nostril and pull trigger, it will blow air in - then you swallow. Its crazy how it works but it does. Absolute life saver for my wife and if my ears get a little sticky I will use it.
Also for those with sinus issues like the OP's son - I start taking an allergy pill with real decongestant a week out (I live in Oklahoma - allergy central) to try to clear out sinuses and ears etc.
Hope it helps someone!