Carlo Ancelotti has what it takes to do well, we don't understand some of his choices but he certainly had his reasons.
He has successfully coached teams of the calibre of Real Madrid for many years, and i think he will be able to do well with Brazil too.
I am very sure of it.
Managing a national team is not as easy as managing a club side. Real Madrid has quality players from every nook and corner of the world. Brazil national team is not like that. So he need to adjust with whatever resources that he get. On top of that, he need to deal with egoistic and eccentric players such as Neymar. Bringing discipline in a team that has no sense of team bonding is going to be his first challenge. Anyway, they have only two matches remaining, and that too against weak teams (Chile and Bolivia).