I've been thinking about how I'd rework Clarence's argument with Emmrich because, as funny as it was, it didn't make sense for Emmrich to freak out about being "much older than Rook" when my Rook is in his 50s.
But since Emmrich opened the conversation by saying he was finalizing his bequeathments, I decided that Emmrich was debating whether or not their relationship is "official" enough for him to include Clarence's son.
This started to freak Clarence out because he's been married before. When he and his ex-wife did their estate planning, it was a very uncomfortable situation for him. There's a difference between facing certain danger out in the wilds, versus having to sit down and seriously think about what you want your loved ones to do after your death, or what you would do if your loved ones die first. The idea of going through all of that again, especially now that he has a son, made him deeply uncomfortable.
So Clarence starts dismissing Emmrich's concerns, basically refusing to even consider the possibility that something could happen to either of them. This makes Emmrich start pushing back even more, (also sprinkling in frustration that he hadn't met Clarence's son yet.)
Clarence tried to use humor to deflect and to end the conversation by saying "well, if we fail, the world's going to end anyway so it doesn't matter what we put in writing." Which Emmrich, as a Mourn Watcher, is deeply offended by.
Anyway, that's their lovers' quarrel.