I had 2 severe asthma attacks recently on my ascent from 80-89' depth. Immersion Pulmonary Edema. Never grew up with asthma, diving induced only. Thought that was very weird too! Told by pulmonary specialist to never dive again. Called DAN, who referred me to Dr. Michael Chidester, WPB Internal Medical doc/ Hyperbaric . You may want to send your son to be checked out, awesome doc, and said I Can dive again!
God Speed to your son