Seeing Charlie again tonight made me think of when Hurley saw Charley at his asylum. A few things stood out to me about that old scene
1) Hurley was not the only one who could see him. A different patient is the one who points out that a man is staring at Hurley.
(note: these are not spoilers, they are transcripts from 'The Beginning of the End')
2) Charlie also says to hurley 'I am dead. But I'm also here'' and he also tells him repeatedly ''They need you'' before he disappears.
Now I dont know how exactly this would tie in to the alt timeline but this scene always bugged me because it was the only time someone else saw a dead friend of Charlies, and the comment of ''I am dead, but I'm also here'' seems a little more relevant now that we know Charlie is alive in another timeline. It is very strange that he disappeared though. Also, I wonder if there is anything more to ''They need you'' other than just convincing him that the people they left need him.