Hurley has been an enigmatic character from the start. I believe he is the only survivor "not" to have been seen on the plane during the flashbacks in the first three or four episodes. That made his desire to have the flight manifest very "convenient," in case he hadn't actually been on the plane. Also, throughout the early episodes, he was always in the middle of whatever action was taking place, usually as a spectator, sometimes as a calming influence. (Perhaps as the consciousness of the island?) And now, of course, thanks to last week, we've finally seen him in a flashback as part of what looks like a newscast.Originally Posted by Reds/Flyers Fan
I think they've waited this long because they wanted to maintain an air of mystery about him, and also because he (along with Locke) is the most potentially interesting character. We know so little about him that literally anything’s possible.
As for Jack's father, that depends on what you mean. We haven't seen his corpse again because, I believe, it never left Australia. The gate agent told Jack he couldn't put it on the plane, so he made one of those "tough decisions" his dad said he was incapable of, and left with the empty coffin in hopes of duping the family into thinking the body was inside. Jack was on some sort of deadline, IIRC.
If you mean the apparition, Jack last saw it when he was delusional. He hasn't been delusional for a while.