I could not breath until I got to the end of your post! Huge huge hugs for you!
(and him too)
So glad he is OK. Definitely speak to your allergist about flying risks. When DD has had anaphylaxis our allergist has been disgusted at the responses from the ER staff...of course she does nothing to force education on them either.
My DD has a tough week after a reaction. She needs Benedryl, Predisone, for at least a week and Albuterol every 4 - 5 hours two weeks. Her system needs time to get rebalanced and healed. She always has had a biphasic reaction, but always within 12 hours of the first reaction. A day later she is totally exhausted. That takes a few days to resolve too. Her body was working hard!
Hoping he is doing better very very quickly!