Hey dude

Sorry you feel that way. 28 isn’t a bad age to get it together with girls and life generally, I know many people who’ve made career transitions or married and started families in their mid to late 30s and made themselves happy.

Start with finding your self worth. It sounds like mumbo jumbo but if you don’t see yourself as an attractive person that people want to spend time with , then you’ll feel like a fraud and project that out.
Become the person you want to be. Read. Experience. Learn. Work out.
Then get social - go out to places where you meet people with mutual interests and talk to all of them. Me I like comedy, Irish folk music, travelling, dancing, reading cheesy spy novels, smoking weed at the tam tams, weights. I’m not very good at many of them but I do them and enjoy them and it gives me a sense of self and opportunities to meet people so when I chat to girls it’s through a shared experience rather than creepily sidling up and blurting put a canned line.

Don’t teach your son pick up. Help him be confident in his self and comfortable socially - it will benefit his whole life rather than having emotionally damaged relationships