Currently Mr PeanutButter is the only charcter that cares about BoJack
Aside from some hostility from the whole Diane thing he seems like the only guy that genuinely doesn't care about bad things he does. I mean what he said to Todd was an amazing insight "Bojack is a damaged individual struggling against a sea of demons" Plus the fact that the guy literally saves his life and doesn't even care when Bojack insults his dying brother. Hell! He didn't even seem to care when Bojack broke into his house and ate all his food.
It seems like if Bojack just tried to pal around with PeanutButter more he'd feel a hell of a lot less alone