Yes, his younger brother by about 9 years. He got a top education at the private schools , Boston Elementary, Boston High School and Boston College. He is what is known then as a Triple Eagle, Boston College having the eagle as its logo. He is Irish but wished to be a Patrician.
Anyway he was a politician that ended up being President of the Massachusetts Senate. That is arguably as important as being Governor so on brother ruled the underworld and the other the legitimate world.
So for example, a state trooper fucked with Whitey and he was teansfered to noplace doing nothing and eventually committed suicide.
The only mystery in this whole thing was why nobody took one for the team and plugged Whitey.