Lost S4 E1 The Beginning of The End

In another mind-blowing fast forward moment, who else but Charlie (presumed dead) visits Hurley at the mental institution? It was actually who he was running away from earlier. Charlie kept telling him, “They need you! They need you!” and when Hurley tried to shut his eye saying he isn’t real, Charlie actually did disappear. So, do we really assume he is dead? And who are “they”? | Click for RECAPS IN FULL.