S.H.
I... am allergic to Sulfa based drugs. AND sulfites... as in food preservatives. So LOOK AT LABELS carefully.
For ME... I get the inability to breathe.
It is very serious.
My Dad was like that too.
He ended up in the hospital once, because of it.
Now you know, he is allergic to it.
Give him fluids, water.
From now on, you will have to NOTE this down, on any paperwork/school info sheets etc., that he is allergic to Sulfa drugs and tell any doctor that he has not seen before.
AND as he gets older, you need to TEACH HIM, how to say himself, that he is allergic to it.