As far as lack of mother, I don't see how's that relevant or strange. There are single parents raising kids all over the country. Who's knows, maybe the mother bailed because she couldn't cope a disabled child.
Emotional father, if that was one of my daughters I would be angry and felling betrayed for a long long time. Not only he had trusted those teachers like many parents do but they've dismissed his daughter's rightful complaints without a single effort to investigate. And to think this happened for years and you couldn't help your kid? I'd be mad at the whole system for life.
The sad thing for many teaching is a job that pays some bills, it's not a career or a calling. I bet those women had no patience whatsoever to deal with disable children but kept at it for lack of a better job. There's no excuse for the district not to investigate such allegations.
My mother was a special ed teacher for most of my young life. I've seen first hand her dedication and personal sacrifice to make those kids succeed and many did. It did not come easy and at times she would feel frustrated and drained. However that would never be an excuse to mistreat her kids.
Those women should be prevented from ever getting close to a classroom again. I'm so glad we have technology today to expose such abuse. I wonder how many suffered over the years in the hands of such horrible people.