it seems your mate thinks he is gods gift to the world!
i have many Acquaintances who do not understand what we go through. when ive been out whincing in pain i get the old age line "its only a tummy ache man up!" the only thing you need to appreciate are the people closest to you understanding, and these people will make a concious effort to understand.
my closest friends had done research themselves after i became super elusive after being strapped to my toilet seat for weeks. if your friend actually took 15 minutes just to look at a forum like this one he will see the extent of our troubles and that missfiring chunks are only the easy part of this disease.
i would advise sitting down with the guy and give him a good explanation of why you are this way. wether or not he sympathises will show if he is worth keeping as a friend.
In truth to summarise this thread, people who do not suffer with it will never fully understand. but i am glad i have caring friends and family that make the effort.
hope you manage to resolve things.