The mother is displaying some real barf-o-rama victimization there.
From a personal perspective: my eldest daughter was a good grade "think outside the box"/apply world knowledge type of student until her fourth grade teacher killed her will to learn. If you want the grim details, FReepmail me. I will just say this woman had NO BUSINESS being around children that age and I hate her guts for doing what she did to my Taylor (who, by the way, at the age of four was playing Simon Says 'Touch your scapula' or 'touch your zygomatic' in pre-school to the confusion of other four year olds and the amazement of adults - she knew these terms from sitting in my sister's lap while my sister studied to be a PA)
From then on, my daughter hasn't put forth any effort in her school work, does enough just to get by and seems to have taken stupid pills.
All it takes is ONE PERSON to kill their spirit.
I think that's exactly what happened to this poor kid, too.
Unfortunately, when you have immature adults who get off on their power trips over little kids, and they will never, ever be held accountable, all we can expect is more of the same.
I endured a situation similar to yours. FReep me if you want, you sound like a kindred spirit. :)