Going by DB Minus/Broly history, the earthlings soften him up and he becomes from thereon an easy solution to any conflict until the Saiyan arc, where he's killed by Vegeta
Going by the CHAD Bardock Special history, he decides to coach his son to conquer the planet but can't bring himself to wipe out the people after what happened with the aliens who granted him the power to see the future. In this scenario, Galu does not become amnesiac due to Bardock finding where his spaceship landed before Grandpa Gohan could drop him, and Bardock doesn't particularly object to Galu killing animals or earthlings that mess with him for food. Galu eventually ends up wiping out the Earthlings by the time that Raditz arrives, and Kakarotto and Bardock just join the Saiyans only to be killed by Freeza at some point.