I don't know much about him. His family was insanely wealthy though. He was pretty violent and one of those bosses that insist nobody deals or uses in his town. He was having guys killed if he found out they were using, etc.
I really don't know why they all turned informant with him. It is true, though. I think they were just that loyal to him.
Not sure about the other clans reprisals, if any. The Camorra are set up so they're pretty independent of one another's clans.

m2w will know a lot more about him than I do.