I had the same difficulty here actually. Lack of knowledge about Tourettes at the time made things extra hard. The doctors were lumping absolutely everything under the TS umbrella and that wasn't helping my son or us as parents. Fortunately we have a really great Asperger's specialist near us and seeing him was the turning point. It's just a pity it took so many years.

Parenting a child on autism spectrum wasn't/isn't the same for me as parenting a child without. Absolutely different.

Keep a notebook. You don't need to make a detailed daily diary, but write down things somewhere that you feel have been important even if you can go back to when he was little. Having all of those things together on paper in one place can help later on if needed.

There are so many excellent resources online these days with information, but you just need to have the time to read it all and that's probably impossible for you right now.

Keep talking with school.

Let us know how your son and you are getting on there.

P.S. Also do remember that regarding other people's "opinions" like the mental health people or whomever... it's not about "opinions". They need to do the proper evaluations! You are his mother. They need to listen to you.