Vito is unable to order the death of his son-in-law though it is apparently obvious to a hysterical Connie that everyone blamed Carlo.
That's true, Lilo. But Vito also knew that Michael would deal with Carlo upon Vito's death. He had to fully expect and even support that. He just didn't have the stomach to see his daughter endure the pain of being a widow. But I'm sure he was still in favor of Carlo getting what was coming to him . If you believe in revenge (which Vito did), killing Carlo was a no brainer.
