Those comments are so rude and inconsiderate. I would have to speak up and tell this person that you do not appreciate his input and then just ignore him (whenever possible) and keep it on a "strictly business" basis. And, tell him and the rest of them that you get your medical advice from professionals.

What GALL!

Did I fail to mention my one friend is a complete arrogant jerk with a sarcastic sense of humor?

No, he's just a cruel jerk.