I recommend not limiting yourself to a neurologist (they are great, but can at times be limited in their scope when assessing root causes; I say this with no disrespect towards any neurologist on this thread). I would recommend you also look into his potential exposure to mold, and other toxins. Mold is easy to assess (urine test), and can create a cascade of issues, including a lot of what you're mentioning here. Sadly, many mainstream neurologists aren't well versed on the topic and health issues associated with mold. I would also have him assessed for a whole panel of toxins that may affect him. I've gone to naturopaths for that, or a functional medicine MD that will look for the root cause of those issues (I would test for heavy metals, and other toxins; there are great tests available for that). I would also have him assessed for PANS/PANDA and also Lyme and co-factors (the full panel). Again, you'll need to go to some practitioners who specialize in those. Key is to find out the root cause for anything neurological that is there. It might take some digging, but I hope you find some answers that can help your son along the way.