Hm. That you describe it as he stopped playing with friends, rather than did not play, suggests that there are other classifications that might be worth exploring. For example, social anxiety. Or social pragmatic communication. Or an unidentified learning issue, in combination with high ability (i.e., 2e), that contributes to anxiety. Or, as several have mentioned, the lack of a peer group. (Of course, none of us here have seen him, vs the professionals who diagnosed him, but there is plenty of discussion about the challenges of differential diagnosis in the field.) it doesn't sound like his Dx of ASD was in the context of a comprehensive neuro/psychological eval, or you would have had individual cognitive assessments to cross reference with the CogAT scores. This may be something worth pursuing.
