He does join his old friend Luke and the Rebels, but that was after Vader showed up and told him to do that and become a secret agent. And Tank did that, and various things happened that I never really followed, but eventually end Tank died to save Luke. I don't know if he ever called Luke "Wormy", though. He should have. Embarrassing nicknames should be spread around.
Luke's childhood friends all die when they join the Rebellion. I'm serious.