Well, if any former employer had pissed me off, I'd probably try to screw them for every penny I could, whenever I could
Brown obviously feels pissed off about something that happened to him at FP, and whatever it was is probably what resulted in his departure. So without knowing what that "something" is, I don't know that I can blame him for trying. For better or for worse, we'd probably never have heard anything about it if JB hadn't turned up on Saturday, either, so up to that point you can't even really accuse CB of pursuing his claim the wrong way. If he really did have any "dignity", he'd certainly have kept his gob shut about it afterwards, though.
All that said, under the circumstances, I'd be as aggrieved as anyone else on here if he actually ends up getting anything.