Jack has a lot of not friends though. Besides, I think Kate's reaction is much more telling than Jack's, as he is basically a lunatic by then. Kate, on the other hand, seems at least somewhat sane. To me, Kate seemed repulsed by the notion of attending the funeral. I don' think she had any animosity towards Locke. Ben, on the other hand would make more sense, but, knowing both Ben and John, I don't see them leaving the Island for any reason.