Hey SL...
I came to understand this behavior, as a boundary violation from my mom. She simply didn't care if I'd just sat down to dinner, had company, or anything. I was programmed to simply sit, listen, and occasionally say "uh-huh" while she ranted on & on. My T told me I didn't have to do this... and to try cutting her short, to see how I felt. When she calls, just tell her I can't talk now and hang up. I still get a slightly sick to my stomach nervousness, even thinking about it. As if I'm bad daughter... not allowed to do this... I have to suffer through this or ELSE.
But after the first couple times, it got easier. Then, I started using caller ID to my advantage. If I was already in an exhausted or fragile place, I simply didn't pick up. Let her leave voicemail and check it later - even if only minutes - because then it really is a one-way message... often she simply doesn't leave a message or says, "you're not there - where are you? I'll try to call you later". I'm 54, do I have to tell my mother where I am, all the time?
Then, I started changing tactics. When she'd claim how hopeless a situation was... I'd suggest this or that way she could take some action. Of course, there was always something wrong with those suggestions. But the next time she recycled that rant - I'd repeat my suggestions. Or I'd ask: well, what have you tried to do, so far? What's the first step?
I think she feels that by relating the same crap over & over, she feels in some way... she's also making me responsible for "knowing" her "side of the story". And it's her way of pretending to have a relationship with me... without actually engaging in one. Boundary violations are what she considers "being close" to me. I see it quite a bit differently. When I've pointed out a few places where she's clearly delusional or paranoid or just flat out making things up... well, she has to go; has something she has to do.
She doesn't call nearly as much now.