[Silverbleed]

LOL she's clearly irritated at everything around her because of her situation and reacts it off on your mom since she's the only other person around - and of course she wouldn't react it off you. So your mom is her victim.
It's good you're telling her not to insult your mother. Maybe it helps if you tell her it disappoints you/hurts you. Grandmothers don't want to do things that hurt her grandchildren xD