I understand the problems - the only thing a teenage boy will agree to carry is his mobile phone and some cash!   My son is a16 years old and hasn’t had a crisis since infancy, so is very stable medically. When out with friends he doesn’t carry the injection kit but takes extra medication in a small pot.  In an emergency, where he would be unable to take more tablets, I would hope that his friends would call an ambulance and his condition recognised by his medic-alert bracelet. I don’t feel they would be able to use the kit and paramedics in the UK are not authorised to inject either, so this wouldn’t be administered until he reached hospital anyway.