I know I'm sticking my head above the parapet here. But what's happened with the OP's son, I think, is a strong example of why we don't need 50 to 60% of people to go to university. Too many students/young people are failing - or just not doing very well at their degree, or even if they do OK, they can't get a job relating to the degree when they leave university. Even though the OP's son is probably quite intelligent, it looks like he probably should not have gone to university.
The OP's son has done Physics I gather? Well I love physics and science and have quite an interest in it. Doesn't mean I could do a degree in it. (And pass!)
When my daughter left school 15 years ago, I would say a good two thirds of the students were practically bullied into going university, including my daughter. She wasn't that bothered about going, even thought she is book smart/academically good, but she went because her teachers encouraged her.
Fortunately, she did very well and ended up getting a 2:1 and is now in a £60K a year job aged 30-ish, and has got a very good life. But some people who went with her, are in low paid, zero-hours-contract jobs now. Also, she's had a few jobs, especially in the first 8 or so years of work, where she was working next to people who had 3 GCSES and nothing more, and were on the same pay scale as her! Yet THEY don't have around £50,000 of debt hanging over them!
DD has paid quite a bit off it as she is a high earner, but she still has quite a way to go to pay it all off.
A large percentage of people aren't going to be able to get a job related to their degree, because there are not enough available. So many people going to university, is why we're running out of tradies. Plumbers, electricians, brickies, carpenters, mechanics, and just general blue collar workers - because too many people feel that they have to go to university.
To be honest, I reckon less than a quarter of people at university should really be there. We need to forget what Tony Blair told us (that 50% of people should go to university!) and just have the top 10 or 15% cream of the crop academically.
I know a number of young people in my village and local town who never went to university who are doing really well. Ditto my DD's husband. On a similar wage to her, and he only did GCSEs and 3 A levels. And 2 of the A levels were C and D! He did an apprenticeship - working for a Government body, and is still there, 15 years later.
Some people just don't need to go to university and will still do well in life. University really is only for a small percentage of people. Not everyone is really academically bright. And that is OK. That's not a criticism. A lot of people are very skilled with their hands and do practical things well.
Many people will do OK in ordinary 'unskilled labour' jobs. There are plenty available ... As I say, a lot of people don't need to go to university, and some should NOT go. It needs to drop down to about 15%.. The amount of debt some young people are in now with their student debt is sickening. It was a TERRIBLE idea from the government for 50% of people to go to university! The debt the country has now - because of this - is horrific.