Who ever the funeral (sorry, not "funeral," "viewing) is for, it's not someone jack was friendly with and certainly not someone Kate was friendly with.
In response to the director's question of friend or family, Jack said "neither." When Jack said he thought kate might have gone, she looked disgusted and said "why?"
So, Juliette is a possibility--if she somehow betrays them again, Ben is certainly a possibility, as is Michael.
Some other random thoughts:
~I think the dynamic of the show will change now. I'm not sure I like that.
~Charlie had a lot of time after Mikial blew the porthole. He could have closed the door from the outside or simply gone out and put on tanks with Des and swum out. He didn't have to drown. I think that scene was handled poorly from that angle (liked it, though. Just wish it would have been quicker).
~I've said from very early on that I think Jack's dad is more central to the story than we know/think. This episode reinforced it.
~Or, could be that Jack has totally lost it. Maybe he's not even a doctor anymore--he's living a fantasy that the hospital puts up with because of who he is and what he's done...but he's totally looney tunes. You never actually see him "being" a doctor...just acting like one. If so, then his dad is still dead....but Jack still sees him. Remember when the pharmacist was going to call him? Jack said "don't bother," and stumbled away. The doctors seemed to ignore (maybe even pity) Jack when he said to get his father and see if he was drunker than him.
~"He walks among us, yet he is not one of us." This might explain Jack's different response to being off the island.