BKD, I'm so sorry you and your children are going through such a difficult period.
My first thought is probably not going to be very comforting, but I feel I should mention that, despite the thorough going over, it is quite possible that something did happen, that he is either unwilling or unable to communicate. (If unwilling, probably for reasons that make a lot of sense to him, even if they might not to another person.) I have had students with various elements of what you describe, and often there has been trauma at the root of it. This does not mean, by the way, that the trauma was necessarily criminal in nature, but the relatively sudden onset suggests to me that it is possible something happened (perhaps at school) that he experienced as traumatic. More than once, the same ASD/anxiety diagnostic categories have been raised with these students, with anxiolytics helping a little bit, but reintegration into school occurring mainly as we were able to build expanding safe spaces and safe experiences in the school (i.e., by acquiring new, controlled experiences of school as a safe, positive environment).
School refusal is a very challenging behavior to treat. From a glance back at your history, I see that you are, shall we say, a reader of primary sources.
You might find these publications to be valuable sources of information:
Handout from National Association of School Psychologists on school refusal, with list of recommended reading:
https://www.nasponline.org/Document...ol_Refusal_Information_for_Educators.pdfOne of the top professional reference works on interventions for school refusal, by Mary Wimmer (update of one of the citations in the NASP handout):
http://www.amazon.com/Evidence-based-Practices-School-Refusal-Truancy/dp/B00JNKZ4EK/
