Goto the ER. Normally they will not cause problems, but he's obviously having some reaction if it's that bad. A bee sting won't kill you if it does not affect you. But if you are allergic to them, one sting could kill.
GOTO the ER and have him monitored. There is no info on RC that's going to help you other then this. He got stung, has had a bad reaction that's serious, GOTO THE ER!!!!!!!!!!!
I hope your family is okay and he's going to be okay!!!