I went through the same thing with my father. he was diagnosed with a form of cancer that was more aggressive than originally expected. The treatment wiped out his kidneys and they were putting him through hell trying to get him to the point where he could re-start therapy. KNowing that it would only lead to a more painful death he told them to stop. That was a hard day. Over the next week we all said our goodbyes, laughed cried, etc. He passed away while I was talking to him (my mom was holding the phone to his ear). Although I know he died with dignity, it was still very tough.

As for your question about allowing someone to die and assisting them in dying, I have my own views on that which relate to my religious faith and I don't believe it is correct to assist someone in taking their own life. However, being a simple minded fisherman/human, there is a pretty darn good chance that I am wrong. I think someone earlier hit the nail on the head, if you are acting out of love then who can judge? My heart and prayers go out to you and your family in this time.