I think we have discussed this before but I'll say it again. I'm sorry, that lady probably means well, but she's a bit of an idiot. The horse wasn't autistic, he was unsocialized...huge difference there.
As for the lameness, that may or may not be a functional lameness like she claims, but if I had a horse that limped that bad, I sure as hell wouldn't ride him, regardless of what the vet said.
Here is the old thread on it... Autistic Horse?