Well maybe not confront him directly in front of her, but I think I would have some fun with him to see how well he did his research to back up his lie. I would ask him about his undergraduate major, where he attended medical school, what he enjoyed most about his anatomy lab (dissecting dead people), his greatest enjoyments and challenges faced during the clinical years of med school, which specialty he chose and why, what year of his residency he is in, why he decided to go into medicine, what hospital or private practice he currently worked at, etc. You get the idea. I think I would really enjoy this “conversation” with him, because I am currently a premed student and could therefore not only demonstrate a great interest in the medical field as experienced by a medical professional but also could provide enough background knowledge on the process of becoming a doctor than this faker might be aware of. Hopefully during my intensive investigation, he would stumble at some point and my friend who herself become aware of the fact that he indeed is NOT a doctor. Of course you could always ask him indirectly “So you doctors really do not make that much during residency, do you?” If he asks why, you can then tell him that you also saw him bartending at the So-and-So bar last weekend. And who knows, maybe you were way off and he is indeed bartending on the side (but typically if you are a doctor in your residency, you will not have the time or energy to commit to another job, since you would most likely be on-call on alternating shifts for some time, depending on your specialty of course).

Yes I would tell my best friend anything she needs to know!

Are you sure he was not a bartender while going through med school? What is he a doctor in... Many professionals with Phd's are out of work these days... is he a vet, physics teach or does he have is doctorate in french? Is he really not a doctor...

My gut reaction is that he has a night job. Maybe he's an intern, and doesn't make as much money as he'd like. I'd ask a few questions first before jumping to the conclusion that he's faking a glamorous profession.