He responded, "The most adult thing I've ever done is leave here."
Sounds like something rude to say. Or at least clueless in its hurtfulness.
The vacation sounds great. Sounds good. Keep busy so he doesn't drag you into his crap.
Maybe if he wants to schedule something with you, keep it light and quick so he can't drag you into a blame fest before he's ready or able to look at his part. Otherwise you're going to spend a lot of time getting the kitchen sink thrown at you.