I've got tears in my eyes as i read that.
Two weeks ago we had to help our precious 17 year old beauty on her way, it was heartbreaking. And like Fatso, it all seemed to happen so fast. I'm not going into detail because I dont think i can bear to type the words, but yes, its all to do with quality of life, isnt it? My girl had been having treatment, and it worked for a while, and then it stopped working and we were offerred more tests and xrays etc, and we just did not want to put her through it. Without going into detail, it was her lungs. And she too had stopped eating and drinking, and she could only walk a few steps at a time, its no life for such a regal, dignified creature, so we did the only thing that we could do for her, and we did it for her.
Your story makes perfect sense to me, thank you for posting it. I'm very sorry for your loss, and I'm very sorry for mine too.