Hello and thank you for contacting us.
from your description I understand that your son may have some difficulties with his social skills. It is difficult to know exactly what goes on in his mind when he is amongst other people, without actually meeting him. He may feel that he does not fit with others or feel very awkward as he may not know what others expect of him or he may not know how to interact with others. He probably feels anxious and his behavior shows a certain level of avoidance. I would assume that the psychologist/psychiatrist who assessed him will have picked up some traits that may need some work. I would suggest that you went back to them and describe all his behaviors that seem inappropriate. They may be able to offer him some sessions e.g. for improving social skills and increasing his understanding in interacting with other people. Also, you can help him by "exposing" him gradually to situations where other people are involved. A psychologist would be able to guide you through a behavioral plan to help him become more familiar with stressful situations and how he can cope through them.
I hope this helps
Please feel free to share any feedback on these thoughts
All the best