Lmao, that's so funny because my sister in law is the opposite.
Are we clones or something? I've had the same issues but avoided them when they came over. They'd pretend to make phone calls and disappear on me for hours because they're "tired".
But never had the decency to ask beforehand if I was willing to. I roasted them 1 too many times for this and they now mostly refuse my help.
She would show she is independent and does not need help with taking care of her children, even if she was struggling cause she had so much hate and pride to ask my mother and my sister's for help, we'd offer it to her too.