There’s no action for the owner to take. The Sonny’s corporation sets the rules to be one of their franchises, they even gave him a two year grace period to think it over, he decided he’d rather do things his way than their, and they parted company. That’s how franchising works, they set the prices, uniforms, decor and menu, and you get the name recognition and customer loyalty.
Yeah, what this guy did was right, but it wasn’t heroic, and it looks to me like Sonny’s was reasonable and so was he.