I'm sorry.

I haven't had such a thing happen to me and damn glad. But I've had very close friends have to deal with it.. (one of them of which's mother died of cancer, another more abrupt) and at first htey were a wreck but... as time went on they became a lot better and stronger. And I'm sure it will hurt...a lot.. and I can't imagine that pain but as cliche as it sounds, although there isn't a replacement for life... there's always those happy memories you have of the loved one that will stay... and I've seen that last bit alone drive my friends to smile and laugh despite the sorrow that such a thing inflicts. I also believe that having a son who cares that much about his father and it seems as though you take much responsibility for his care... is something any father would be proud of and be glad to have. Although you may not feel as though you've repayed him.. Maybe you have just by being a caring son.