How to help my son cope

Son is a senior, has played for 7 years. Worked his tail off to turn himself into the best player he can be. He’s not a spectacular athlete but from my biased perspective he’s probably an average player. He’s seen about 20 snaps of meaningful varsity football and can’t get over feeling like a failure. It’s shredded his confidence which has rarely been an issue for him.

My wife and I have consistently told him that he should be proud of all the work he’s put in to get stronger and recover from significant injuries and the fact that he’s consistently competed in practice and that contribution to the team is important even if it goes unnoticed. More importantly, what a great teammate and friend he’s been to his fellow players

I hope that he will eventually be able to come to terms with it but right now he feels ashamed that he believed in himself and put so much time and effort in. I’m worried about his well being and looking for some perspective and advice in how to help him. I know this is probably not the perfect forum for the question but I figure there are a lot of coaches on here. Thanks.