This was the hardest thing I ever had to do...
I'll bare my soul a little bit.
I watched my father waste away over the course of many years, the last few weeks of which were in a hospital room with all types of machines and what not.
This happened when I was young, and it took me quite a few years to figure out how to constructively deal with it. The solution I came up with was to embody what I believe were his principles and ethics as a little voice in my head; now, when I wonder about things I can almost have an internal conversation about them - obviously, this is "thinking", but it is a little different. The voice quite often tells me that I'm full of crap or what not, and I find it very hard to fool this voice, despite repeated tries.
Also, I find that experiencing such a loss reminds me of my own mortality - I am constantly trying to get things done now because I am acutely aware that tomorrow is both so close and so far.
Finally, this reminded me of this:
[video=youtube;vmC3rJR7E98]http://www.youtube.com/watch?v=vmC3rJR7E98[/video]