Hi, when I knew my husband was acting differently we had his Doc refer to a Neuro clinic. They did 3 hours of testing to come yup with a diagnosis.
I wonder if you need to kick it up a notch and make an appointment with his Doc without him, just so you can get advice and next steps. Maybe he'll end up coming with you if you tell him you are so concerned you made an appointment, and maybe your insurance company website has a search for providers so you can see their ratings and choose a Doc that's a better fit. Good luck to you!