You're right that he should pack it up and get rid of it. Mine was never going to and I didn't want to see it. I know what you mean about him not taking charge. At some point, Hopefully he will own this. He may not. Make sure you have a way to channel the anger so it doesn't eat at you. I know it does right now, but eventually you want to be able to get angry, deal with it and let it go.
This isn't a ride for everyone and you don't have to walk on eggshells. I think we do that most when we're looking to "fix" things. "If I do this, then maybe he'll/she'll come back". It doesn't work that way and you wouldn't want it to. Not really. If it did then you'd spend way too much energy trying to second guess them and make them happy in advance so they wouldn't leave again. That's not a way to live. When you're stronger within yourself you can decide if the opportunity presents itself whether or not this R is truly salvagable. I know how hard it is. All that I've learned through this mess has been hard won.
Just remember that any choices you make need to be made with your head too. I vote for a 24hr (in some cases longer) cooling off period for you to think.
While Daddy may be crazy (at the moment), I think I'd pull him aside and ask him not to say that to her. It sounds like he's using it as an excuse. Diminished capacity my a$$.
