This black hole of common sense just said Crazy Nanny was "eccentric" with her art supplies and that's why there are sponges and dish brushes instead of regular paint brushes.
Abbie, like most autistic children (at the time Crazy Nanny was around Abbie was a child), has serious problems with fine motor control. She can't properly work a paint brush.
The sponges and the larger dish brush let her participate in a way that's easier for her needs!
The sheer cluelessness...the complete lack of intellectual curiosity...
Feel free to ignore, but if it's looking like your grandson might not be all the way there, a doctor's note from his pediatrician regarding incontinence will likely get his public school district on board. That can give him some more time to get up to speed while still allowing him to benefit from preschool.