Before Sonny sent Fredo off to learn the casino business, what exactly was his position? He was obviously shadowing the Don, and he even got to sit in on important meetings ...i.e. he was there for the Sollozzo meeting. Its pure speculation, but it seeems Vito may have known Fredo's limitations but never thought he had it in him to turn traitor on his family, and perhaps he would not have if Sonny had not died and Fredo never had to be angry about being passed over. But I wonder...was he on the muscle end? Was he made?