Right...no need for a different flu shot as the living viruses do not evolve at all, right? MRSA didn't evolve either?
Some other examples:
http://listverse.com/2011/11/19/8-examples-of-evolution-in-action/
But don't try to convince him, it won't work. As long as he knows you made a rational decision based on a lot of evidence. He might not accept the evidence, but sure as hell cannot refute it.