I wasnt talking about who his special son was but that Vito choosing the path of crime must have influenced Fredos and Sonnys decision to choose a similar lifestyle (of crime) by this it was Vitos fault to a certain extent his children turned out the way they did, I'm sure as a father Vito didnt want the same lifestyle for his children. Even Mike his favourite son fell into the criminal lifestyle because of Vito. All this shows that Vito was well a bad influence on his kids which makes him a bad father.