So his self-interest is genuine, but he's also capable of more kindly behavior?

Yeah; my hazy recollection is that he's got a streak of pretty strong devotion to Mal.

I had worldbuilding problems with the show Me too. I heard, re: the Asian profanities but no Asian characters, that they'd intended to make there be more Asian characters, but that that got nixed somewhere along the line, and so you had the leftovers (language, writing), but not the characters themselves. I don't know whether that's true or just a plausible explanation created for something that otherwise would be pretty dang inexplicable.