I suggest calling your local mental health office for advice on how to deal with this.

If she hasn't changed in all these years, it's unlikely she will now.

You MAY want to give it a short trial - say 2 weeks - and tell her, in essence, "No bitching" and that you will call her on it every time.

If you do talk to her again, you can try what a friend tried on me many many years ago: "Ask me a question. Ask me what my favourite colour is, what movies I like." She did that to get me out of my head and at least CONSIDER other people around me.

Sadly, I think the bottom line is she will keep spewing vitriol till she dies. You are not obliged to handle an ongoing running sewer of human behaviour.

This is MUCH different that being asked for advice by people you know...this woman is asking for nothing except a target to continually dump on.

JMO