Yep, 100% a rat. He got hosed on both ends- fellow mobsters and the feds. His wife was extorted a lot of money from a mobster, as he knew that nobody would come to her aid. This continued until she dropped dead.
Who was the mobster?, some guy nicknamed "The bug" or something like that wasn't it?
I agree, Casso is a rat.
Say what you will about guys like Carmine Persico and Bruno Indelicato but they are 100% cosa nostra, they didn't rat.
Casso and Massino were both gangsters on the wrong side of the law until it didn't suit their purpose anymore and they flipped.
Same goes for Bill Cutolo's son, he was a gangster until his Poppa got killed and he knew he couldn't do anything about it so he ran to the law expecting help and protection when both he and his father had always operated on the other side of law and order
