Hi meagain,
This probably isn't of much use to you but where I live my partner works for an organisation linked to Cahms, education, social services and youth work and they work with children just like your son,some have odd, some mental health some adhd etc, I'm not sure if its specific to our area but they work with supporting the children in school and undertake activities with them in the summer and out of hours, like you say its good because the children/young people do get to meet other individuals who are experiencing difficulites , they also work with the families to assist with coping strategies. Good luck