Experience would mean he's taken out a bunch of people's appendices and nothing bad has happened. Which still wouldn't prove that the appendix has no purpose at all.
He's a pathologist, so if he has removed someone's appendix they'd probably be dead. Pedantry aside, your point still stands.
I've done a fair number of autopsies and have never even heard of someone ending up on the autopsy table secondary to an appendectomy. I'm sure it's happened, but, on balance, if the docs say you need an appendectomy, they're probably right.
Just making a dumb joke that if it's the pathologist that's the person removing an appendix, they're probably dead already.