Sorry it's another long one, but hope you might find some bits useful.
Re the denial; don't underestimate the very powerful effect of other students telling him 'of course he can't be failed just for that.' 'they wouldn't send you yr2 timetables if you weren't able to continue' etc
The desire to convince each other that bad things can't happen is high, (I found my cohort mainly incredibly naive for their ages) but the others wise up just in time, leaving more vulnerable students to carry on believing while they are busily rectifying things last minute. IME they wont necessarily then tell the vulnerable student.
(Not so much with Ds but I found myself trying to convince vulnerable students not to FAAFO for others enlightenment)
If your Ds wants you to try and sort this out, I'd suggest getting him on repeat saying I have asked my mother to advocate for me' 'I have brought my parent for support navigating X' He needs to learn to take the lead in this to utilize your support.
University staff are often dealing with parents who wont let their YA's grow up, or think that because they're paying they are entitled to make demands, and quite often staff decide they are helping the student by stopping the parent being involved. (often are tbh, but not always) They understandably want all students to be independent adults. (regardless of their ability to oblige)
Ds handled most of his his M.Eng 1st yr issues himself though pretty poorly, (outside of SFE which was a disaster) but struggled with the course not being what had been sold to him, as it changed from a focus on practical learning by doing, to theoretical, as he started, and he just couldn't understand they could do that.
But when he changed courses to one requiring lots of communication and soft skills, and nuance, he unsurprisingly ran into issues left right and center. Everyone said head off to maths or IT as clearly 'easier' for him. Not what he wanted to do in life.
I refused to go in to meetings to help him unless he made it clear that he was dragging me in, not that I was infantalising him. Also made him lead meetings, and state clearly what outcomes he wanted. TBH at home I was getting him to write his agenda, what had gone wrong etc, and the magic words "How can I resolve this?" (known as the big question to be repeated often if feeling overwhelmed) and would periodically in a meeting remind him to look at his notes if he got diverted by whose 'fault' things where.
(Part of home educating him was attempting to educate him in how the NT world actually worked, and where his weaknesses in dealing with it where and possibly why, including lasting earlier school damage, as well as understanding his strengths.
They often need this and it takes time.)
Even then as a fellow student, I repeatedly had to explain he had effectively gatecrashed my uni, not the other way round. Assumptions about parents are strong.
I understand the hope that staying in education will give a 'safe' space to mature, grow and problem solve, our goal too. But IME so much background work has to also be ongoing for it to really succeed. Amongst other stuff Ds was encouraged and helped to work alongside study, not taking on work at critical points, but experiencing lots of different situations and societies requirements all the time.
Lots of people will question if students like these should be there at all.
Universities are run as businesses and want bums on seats. That's the real reason for the huge growth of the support services industry around them.
Tutors often don't share the view, many pre date inclusion for all, and can be reluctant to be particularly supportive, as well as simply being quite disconnected from student support services and different learning methodologies.
But the vast majority don't want to see students fail. However if they think a student isn't up to it, them failing at end of yr 1, is the best option. There's always a natural 'no fault' reduction in numbers at that point.
Them making it to yr2 then failing, isn't great for the tutors either.
I can only say that D's has come a long, long, way from those days of intensive support to just get through daily, and despite Covid knocking him clean off track as the bottom dropped out of his industry, was able to use transferable skills gained from his degree to head for a different career, and holds a good useful position.
But although he masks well, it's still all at big daily cost, and some bits still easily revert under pressure. He has better coping mechanisms. (some maladaptive worrying ones too.)
He still hasn't succeeded at independent living. It's a long road, and if you can future plan for yourself potentially having to be around more and longer than expected, as well, IME it would be wise, regardless of your hopes or actual desires.
Keep figuring out with him what the way forward to independence is, regardless of if others get the need to be doing it, to prevent the sink part of sink or swim, or not.