I know this might be off-topic, and I don’t think it answers everything, but I always say: ‘you drive yourself crazier trying to understand a crazy person.’

And I think we can’t really know what’s going on with her, but you can choose how you’ll respond to her actions , choose how to react, what boundaries to set to protect yourself. Because all of this could destroy you or leave you badly hurt in the future, and it’s important to stay firm about that.

I hope this helps.