The scene where Tony comes back from interrogating Jack Massarone is the perfect example of how unhinged he is.
He believes he has the ability to read people, then when it fails, he comes back and says "What am I, a mind reader?" Later on, Chris suggests Tony B could be the one to kill Jack and Tony says "THE MAN IS TRYING TO GO STRAIGHT! DON'T YOU GIVE A fukk ABOUT YOUR COUSIN?!" And then seconds later, he says Tony B is useless for the exact reason he just told Chris.
He should have went back to Melfi sooner.