The narrator explains that Daniel is right about Charlie: he's an asshole to the core. In time, he'll settle into being mean. However, before he marries, becomes a politician, changes his name to Charles Bay, and betrays his wife and constituents every chance he gets, he will do one good and selfless thing for Daniel. It'll be the last good thing he ever does.
Charlie's future suggests that his isolation in the present has dire consequences. Also note that the narrator's interpretation of his life as a politician bears no resemblance to what politicians are supposed to do: connect and serve people.