I'm going to move away from the medication questions for the moment because after reading your messages, there is one single thing that stands out for me and I've quoted that above...

So, at the Neuro appointment coming up, if he is diagnosed correctly and the diagnosis includes AS and a Tic Disorder / OCD (remembering too that people on autism spectrum can have difficulties with attention and have OC symptoms as well), then you can find a whole new direction in which to help guide your son. I hope the specialist you are seeing does have good knowledge of the autism spectrum as well as tic disorders and that you get some answers.

I also wonder how he's doing at school? Have the teachers talked to you much about how they see him in class? Have they been helpful???

If he does get an AS diagnosis then it will open up a whole new realm of practical help that you can use and the schools can use to guide him through these difficult young years, and with good understanding of his strengths you may find it will work better than any medication that's available, believe me.

All the best with the Neuro appointment. Please let us know how it goes.