How are you doing today?
It’s tough to see someone making bad decisions, but watching her do this at the moment seems to be causing you a lot of pain at a time in your life when you could do without extra stress.
If you were my friend I’d be advising you to take a little time away from contact with this woman, not to break off the friendship, but to be in touch a little less often than you have. That maybe sounds harsh but you’ve likely got very little influence on the decisions she’s making, so it’s a case of being witness to these glaringly red flag situations with little control over them which will be hard on you.
In short look after you. She hopefully might work this out herself but you probably can’t influence that.