Well, her family should care. Instead of putting that knife down, she could have stabbed you with it. If they don't worry about her behavior, I would not visit again. It will be too late for them to act if she does hurt someone. It is sad, too because she does not really know what reality is anymore. But if my spouse wants to continue to visit, they could go themselves. She needs to be in a memory unit somewhere so she doesn't harm herself or someone else.