OmniSpectra
He needs to eat a Senzu Bean and just Kai Kai to his family and get out but there (forget even talking to cooler, he shot him in the back like a coward anyway). First he needs to find them I guess. Being under Cooler would actually be worse than Frieza with his inferiority complex forwards Frieza, but both are still bad. Now that he knows about his Evil Saiyan transformation , he needs to learn to master the false form before he reaches the real one I guess. He really needs to learn spirit control to temper his destructive impulse though (if he master it he might even purify the form to become even stronger), Broly could use it too now that I think about it.