Sounds like it could be depression, to me. I developed a good "song and dance" routine, i.e. a pretend act at an early age, in order to "cope".
Although I started planning suicide at 10, I kept the "act" going until I was 16, when it fell apart.
I wasn't able to isolate - which I wanted to - so became suicidal..
ADD/ADHD and Aspergers had barely been "invented" in my day. (I'm 65). All I knew was that I didn't "belong", had high anxiety levels about EVERYTHING, and wanted to die, most of the time. Didn't talk about it to anyone, as when I'd tried, I got the usual responses of people who hadn't experienced depression themselves. I.e. - dismissive.
Help came via having a mentor - one to one - non-family, older family friend who taught me sailing, told me great humorous stories, and helped me build some self-reliance and self-worth. Sailing, being largely solitary, or semi-solitary, allowed me to semi-isolate, but to take some responsibility, co-operate with others, whilst not having having to compete with others.
Getting someone along to your home who is familiar with depression, for a meal and a chat, might point a way forward.
Clearly your son is going through a tough time, but he's fortunate to have parents who care enough to be concerned, ask for help, and be open to suggestions. Hope there's a good outcome for you all