Exactly what I am thinking. There is a way to make a point without calling someone's mom hateful names when you don't even know the woman. I would be pretty ticked if someone called my mother those names no matter what she did.
The facts may present themselves in this misunderstanding/accident, but there is a way one conduct's themselves tactfully when addressing concerns and giving out advice.
Margecat, I am so terribly sorry about what happened. There is no way now to determine what may have helped your poor kitty, but the one thing I really am disappointed and upset about is that your mom did NOT consult YOU first. That is the biggest mistake in this horrific tradegy.
She may not have wanted to be burdened by the constant yowling and health problem. There is no telling. The only way you will find out is by talking to her face to face.