When I was coaching HS basketball, that was my experience. The parents of one player had him brainwashed to the point that he wouldn't contribute off the bench because he believed he should be starting. His points came mostly against second team opponents and I found his scoring invaluable, but when he started he disappeared. So I put him back as a top sub and his parents convinced him to stop playing hard until he started, no matter how much I tried to convince him otherwise.
I can see a high school kid thinking that way but an adult who thinks the best way to start is to not try is pretty messed up. Just out of curiosity, how did you find out it was his parents telling him to quit trying?