Your new information changes my opinion.
Even if she was only a danger to herself, she should not have been left alone.
You didn't know that the husband and other relatives were worried that she was going to kill herself.
When you find that out, you just wonder why anyone would leave their kids alone with her.
I feel like no one was really looking out for the children.
Oh well, hindsight. It would be nice to prevent something like this in the future.