Who is Frankie from To Have and Have Not and what is their importance?

Frankie is described as Morgan's loyal, good-hearted, seemingly dumb but really deaf drinking buddy. He hangs around at the waterfront doing odd jobs, all while looking out for opportunities for Morgan. While Morgan is eating lunch at the Perla, Frankie delivers a rolled up paper he was given by a Spanish boy at the dock. The paper was actually a photo of a black man slit ear-to-ear with marked with the caption: "This is what we do to lenguas largas."