I'm going to give him a bit of a pass. His father *just* died. When my mother died, I handled it pretty well--but the biggest thing was that my patience was just a lot thinner than usual. If we saw him do this stuff again a year from now, yeah, I'd agree. But when you're grieving and in a high-stress environment, the things that would already rub you the wrong way become even more grating. And he doesn't have much ability to retreat and recharge himself, given where they work.
When Caroline first started talking about her parents as narcissists, I had a hunch that she was part of the online world of armchair diagnosing people you don't like as narcissists. Her saying last night that she is "the scapegoat" seemed to confirm it--she's using all the lingo they use. It's a kind of bizarre subculture. Of course, lots of people truly are narcissists--but there's a bit of a subculture in which people constantly affirm each other that they receive bad treatment. Her parents may be truly awful, but her own behavior makes it hard to gauge.
And I do think that Kate and Josiah were unnecessarily awful by doing the speaker thing. They weren't the best to her, but they were pretty good, and they gave away some of the moral high ground here.