She was wrong to say that about her son. 

How many relationships have ended because one of the people in it thinks the other one is out of their league? I know a lot of people who have felt insecure in relationships because they think their partner is much more attractive than they are, and they worry their partner will leave them because of it. Sometimes that is a genuine problem in dating. If you’re with somebody who thinks they’re much more good-looking than you, they will likely treat you worse than they’d treat a partner that they see as a genuine equal. 

I think we should care a whole heck of a lot less about looks, but even if you, as an individual, don’t care about how you, your partner, or the public at large looks, there will always be somebody who has a lot to say about appearance. Your boss will judge you if you don’t wear proper office attire. Your mom will be concerned that you «let yourself go» if you gain weight. You’re going to be treated better in most social situations if you’re good-looking than you would be treated if you weren’t. That’s the sad truth about the world we live in. 

The couple in this story is happy. He loves her, and she loves him, but his family thinks she could do better than him, and they’re not shy about making that known, even if it hurts his feelings.