I know that this is not specifically about your son, and in the whole I agree with you, but there are things that students can do to get money/save money.
Some deliberately choose a local university. Some areas of the country have lots and others have very few so this can be pretty unfair. It does save a massive amount on rent costs though. My DD is at Newcastle and there are quite a few in her course who live locally and commute in.
Many people take a gap year and work through that to save up for uni. Some are able to use this to get sponsorship through uni - a friend of my DS's has been sponsored through by the Navy and is now in basic training.
Some jobs will allow transfer between uni and home branches - McDonald's do this and I'm pretty sure some of the supermarkets as well. This means students can do a lot of extra shifts in the holidays when it's less pressured and only minimal in term time.
The holidays are pretty long, especially the summer ones. Most students will work through the summer holidays, often bar work (my DS) or retail but it usually possible to get better paid office work. I did data entry all one summer - deadly boring but well paid.
If the student is ND like your son is then there really is a lot of support out there. The DSA people are very keen to offer as much support as possible as they really do want you to support disabled students through uni. Most unis have study support, and DSA can also unlock counselling, my DD was able to get a single adapted room, taxis to uni etc.
All universities have hardship funds and if a student is struggling financially they can apply to them.
I agree with you that going to uni is expensive, and with rent rises and cost of living it is getting worse. But there are things that can be done, and support that can be accessed.