Sounds like he might be in the market for a valve replacement (probably) or a valve repair (maybe). Both require cracking him open - not a minor deal. A valve replacement comes with all sorts of long-term fun as well.
If what he says is true and accurate, then it must not be so severe that they are opposed to monitoring him and delaying the surgery. The fact that he doesn't have any symptoms is something he should share with his doctor. Maybe it is a minor deal and they'll be happy he is getting in shape. We don't know <----- that's the problem
I'm not a doctor or strength coach. This guy just doesn't seem to know what he's doing and a quick conversation with his cardiologist would clear the air very quickly. He could call them and get this answered pretty quickly.
If they come up with a minimally invasive aortic valve replacement with all the pros of a mechanical and pig valve with none of the cons of either, then sign me up too. Otherwise, I'd be making informed decisions about what risks I take if I was him. Going off how you feel is best left to teenagers.