I appreciate that. On another note, I had never had a close family member die before, much less of cancer, and I guess I had the idea that it would be like a movie-- either painless and instant, or Godfather "last words" style. I had no idea that cancer basically makes you go senile right before you die, causing you to freak out for a day saying things you've never said, then go open-eye comatose for another day, finally becoming unresponsive until your breathing stops.
Your experience isn't unique to cancer. Unfortunately the phrase "keeping someone comfortable" doesn't mean what people would like to think it means. Having seen the pain and distress which so often accompanies death in this day and age, I've made damned sure that my medical wishes are very well known.