I truly feel for you. My son is now in his 40s, and a wonderful man, dearly loved by the family and friends, and liked and respected by colleagues.
Like your boy, he had a hard time at school. He did not have behavioural difficulties, but always found it hard to get on with other children. We thought it was because we were in our late 30s when he was born, and all our friends' children were so much older, so he wasn't used to relating to children of his own age. This was not from choice, we wanted a large family, but he was an 'only' born just before our 9th wedding anniversary.
He was 'different' very 'old' for his age. Also very mature looking, and at four he looked like a seven year old. People expected him to behave like a seven year old, when he was four.. He was bullied both mentally and physically, and hated school because of this!
He had a very high IQ, but constantly underachieved throughout his school career, and later at college.
And he has always had very low self-esteem, which has really upset us, as we (naturally) think he is wonderful.
He lives with a woman he loves, who suffers from severe depression, and who makes his life an utter misery, though he never days a word against her. (I'm not being spiteful, we love her too.)
He has spent some time in the Priory, and has had many sessions of therapy and counselling.
In the last week we have been told that there is a possibility that he has always suffered from Asperger's Syndrome, which would explain his problems throughout his life. We have to wait for a diagnosis, but are praying that it will be positive, then at last he can receive some appropriate treatment.
So PLEASE keep trying. Ask them to go down EVERY possible avenue, and get him the help he needs before he is sentenced to a lifetime of misery!
My very best wishes to you, and to the boy