If my memory serves me well, the New Zealand singer-songwriter Paul Metsers used to have an interest in this. I'm sure I remember him running an advertisement in "Folk Roots" [ as it was in the 1980s ] asking about songs about autism. He certainly wrote 1 song to do with that very subject. I've no idea how you would contact him these days, but it may well be worth your while asking him. In any case, good luck with your work.