Who is Batiste from Half of Paradise: A Novel and what is their importance?

Batiste is the grandson of the freed slave who accompanied Broussard's grandfather to Louisiana. He has been with the Broussards since Avery was a boy, and he is the only real family Avery has left. Batiste often acts as a hired hand, but it is clear to everyone that they have a close relationship. Batiste is the one person that will stand by Avery until the end.