Hi OP. I was that university student, but this is now 35 years ago, I kept it bottled up and masked it very well and, although I struggled through and just about graduated with a (mediocre) degree, it took me decades to get over what was a very scarring experience. I couldn't talk to my parents (who were just so proud of their 'clever daughter' for 'getting in') and there wasn't much support within the university. Basically, I didn't have the organisational and study skills necessary to manage the enormous workload, and I masked my lack of social skills and unhappiness with workaholism, binge drinking, binge eating, chain-smoking and casual sex. Not recommended!
So I would urge you not to give up, frustrating though it is. If your son is making appointments with the various sources of assistance (academic tutors, GP, counselling services, study skills if this exists) but failing to follow through, can you go and stay for a few days and sort of chivy him along to the appointments? Meet up afterwards for a nice lunch/dinner? Can he be persuaded to engage with the careers service, so that he has a goal, (or at least thoughts about)for his studies/life after university?
Two very practical things - routine (same time rising, exercise - which is very important for regulating mood - getting his laundry done, cleaning his room) and a book I came across fairly recently "How to be a Straight A student". It has lots of good advice on study skills.
If it turns out that this is not the right course/place for him, he will be able to talk to you and the university support network about that, and be in a better position to change tack in a planned, rather than a panicked, way. And if it is the right place and course, and he's just taking a bit of time to find his feet, the experience he gains in overcoming difficulties will boost his confidence. I think what was the worse thing for me was feeling I had no choice but to keep going on this path to the bitter end, even though I knew I was underperforming and couldn't pull it around.
The adolescent brain goes on until about 25, apparently (oh joy!) and some young adults need a lot of help and advice to reach their potential.