Wawwww how time flies, he was just a baby..... congratulations Maha,
Personally, i informed the P.E. teacher that if my son requested rest during the class, he must have it at once (since he is having a low HB) and that if by any chance he got hit in the stomach, they should let me know at once and call me by phone.
My point is that i wanted to inform people who may be in situation that has to do with thal (like PE teacher and actually she didn't know what is thal so i told her it is just a kind of anemia).
I think that informing other teachers will not have any benefit to me, on the contrary they might treat him differently or with extra caution which is something i don't want
Good luck Maha, and keep us informed how things will go
manal