I can totally sympathise and understand.
I am constantly picking up the bits of my parents' lives, mainly my mum's. They're sepearted and the divirce has been dragging on for over a year. I'm stuck in the middle as they communicate through me - and its very messy.
I had to cope with my mum having an affair, my dad finding out and all the fall out. Then my dad getting a gf (after mum told him to), then mum going berserk and trying to kill my dad (police were involved it was so serious). Mum was dd's carer while I was at work and I had to stop that as I was so worried about mum's mental health.
Mum is still fuming over dad's girlfriend. Then mum got dumped by her bit on the side.
Oh, and my brother hasn't spoken to my mum in years so I have to listen to all that from her as well (she blames me). And my mum hates her mother so I have to listen to non-stop moaning about that as well.
Its never ending and I know she will never change. Sorry I can't offer any advice I do try to not really listen to her, just sit there going uh-huh and nodding!