Edit: I meant to ask if they helped the Allies when they invaded Sicily?
similar questions have been asked before
https://www.reddit.com/r/AskHistorians/comments/82pl7a/how_did_mussolini_overcome_the_mafia_in_italy/
https://www.reddit.com/r/AskHistorians/comments/4o2kiq/what_role_did_mafias_play_in_the_second_world_war/
these should answer most of your question