Ive just divorced after a long marriage. The divorce was awful and I crossed boundaries with my Dd for a while. I am now ensuring I don’t do that any more.
I know that when it was happening I was in such a mess that I couldn’t help myself. I needed someone else to know how I didn’t deserve the horrible things my ex was doing.
I think the only choice you have is to tell them that you just can’t listen to this stuff. It will be difficult for them to stop it and so it will take a while.
Everytime one of them starts you could start “offering solutions” Ie leave, get divorced, contact Council etc etc etc. As it’s unlikely they will do any of these things but you can then explain that you won’t/cant listen to them anymore if they won’t do anything to help themselves or change the situation.
They probably need to find an outsider to vent/unburden to. Can you advise them this?
I am currently having NHS CBT therapy to help me get over my abusive marriage. It is helping a lot. You can self refer but it took me 10 months on the waiting list.
I also got referred to my local MIND charity and had some subsidised therapy that cost £25/session.
I think I have come to the conclusion that if I am to stop whining to my Dd, I need someone else (a professional) who can help me overcome this negative trait. It does me no good, and in the long run it’s helpful to everyone.
Best of luck.