have SALT ever done an evaluation on him? I cant remember the test the therapist did with my boy but it showed misinterperetation and lack of semantic understanding. Also that if things have a couple of parts to them then he hears the beginning and the last part or only hears the middle so just totally misses what you were saying.

As for the logic in thinking no socks cant go to school. It could be like others have said, its just such a literal thought process. At some point he'l have heard that you cant go to school without socks and thats then become a solid rule in his mind. I think this rigid throught process I have been reading is atually a part of SPD but initially my thoughts would have been that that is a spectrum type trait. No flexibility of thought or taking things too literally.

The PECS sounds like a good idea - I have been trying to eliminate our use of them and get my boy more verbal but then CCD went into school and suggested he use them even more so who knows lol.

Hope you find some way to work around these things