I never understood why Preach didn't attend Cochise's funeral at that end? I guess it works dramatically but it doesn't make much sense. He was Cochise's best friend and he's just kind of hiding in the bushes wearing jeans and sneakers.
share2 reasons, IMO, why Preach waited until everybody left:
1) he didn't want anybody to make him change his mind about leaving. I think Cochise's death made Preach realize there was nothing but jail or death for him if he stayed in the hood.
2) preach and Cochise had a connection that was above and beyond anything that could be understood by the others in their circle, and Preach simply wanted one last moment alone to say what was truly in his mind about losing his best friend.