Not sure if this helps give context - My kiddo, privately educated until 16, had an ASD/ADHD meltdown when they left to attend a state 6th form. Tried again second year but was still awaiting diagnosis. Rinse repeat. Two years behind - nearly three.
Is now about to start, at 19, an access course at the local tech. It was a simple case of online application, proof of GCSES (which were excellent, 10 all 7-9s, which I am going to guess OP’s son’s were). At 16 the 6th forms don’t engage with the parents - the application has to be done by student. They only contact you if there are issues but you can see what’s going on on the parent portal. They are very much ‘the child is in charge’ and parents need to butt out. The Access course which is usually at an adult ed/tech college is the same. At 18 an applicant is legally an adult, adding my/parental details was optional. As my child has no Level 3 qualifications and will be 19 when starting, it is also free, so again, no need to contact me.
Most of the access courses run by the local group of colleges (eg Activate Learning) are actually on line. Attendance in person is currently only required if doing certain STEM subjects or a practical one, like Art & Design, though the timing suggests this took place before COVID, so perhaps it was all in person back then?
It would, therefore, be perfectly feasible that he sorted this out without any help. Nearly every university we have looked at accepts Access Diplomas on the proviso that they get distinctions/Merits (3x distinctions, the max score is equivalent to 148 UCAS points - ie 3As at A Level). Not Oxbridge of course, but all the London colleges bar Imperial, and all the Art Schools. The post code of the institution is what counts, rather than that of the child’s address, and most Access Course providers are listed as eligible for a contextual offer - my child will be eligible despite our personal family circumstances and [acc to the EA leaflets] a ‘desirable’ post code, although the ADHD/ASD is also a consideration.
As I said above - I think OP’s son showed remarkable resilience and backbone doing this under his own steam. Whatever OP may feel, the family culture will have communicated implicitly that his failure was not acceptable (choosing a grammar school for example is an express demonstration of the importance attached to academic achievement). I remain deeply saddened that an 18/19 year old felt that he had to go to such lengths to hide what he was doing and that, when he passed, he still didn’t feel he could admit that he had an Access Diploma rather than A Levels - it was only his first from UoE that it gave him the courage to confess.
If I were the parent of a child doing this I would be mortified that my conduct made him feel this way. And I say this as one half of a high achieving academic/professional family - DH went to Cambridge, I have 3 degrees and am one year off a PhD. We could care less if our children go to university, we just want them to have goals and a career that lights them up. We bend over backwards to communicate this to our kids. We are not the benchmark for their lives.