So sorry that happened. Even if they suspected something, I think it was poorly handled by the principal. I agree that a letter to the superindentant is in order. Personally, I'd have the attorney send it.

I wish I had more words of advice since my mom had MS, but we lived close enough to the school that I walked. The people at the school only saw her during events or when voting. I do know that some didn't fully understand and were rude to her at times.