"They didn't get along real well, but Lily would still stop in sometimes."

The two troll sisters had something of a rocky relationship, worse after their mother died. He'd gotten to know Holly first, mostly just because of how frequently he was at the Trip Trap, and Lily through her. Things were okay for a while, even if he had to be this weird go-between when she decided that she wasn't going to talk to her sister, and then Lily disappeared and everything went to shit.

"I didn't go out of my fuckin' way or nothin'."

It just sort of happened; after enough time and drinks and shared hardship, they grew on him. And, probably, he grew on them, too.