Poor man! If only he'd been in a class where Kodali lessons were given. He might not be the best singer today, but he would be better.
Kodali is all about training the ear. Teachers might sing a simple command, like Good morning. The students then reply in the same notes used. They do get better.
I remember one student who desperately wanted to play violin. She could not hold a note, so you can imagine her mother's horror. Still he allowed her to take up lessons, and believe it or not, she began to improve.
I hope the link below works. I found it on Facebook years ago and I still can't watch it without cracking up.