Grey knows that you did your absolute best for him. There were no wrong decisions made in his behalf. Your love transcends all. Grey and all creatures easily forgive our imperfections and so should you forgive yourself for any perceived mistakes. We humans are so hard on ourselves, especially concerning our beloved furkids because they can't speak and tell us exactly what's bothering them and what would make it all better, so sometimes we look back and get a case of the "should haves". He's at peace now and, even though his memory still tugs at your heart, know that every effort that you made kept him w/you and comfortable for just a little while longer. It's what you both desired, to be together. And you will be together again, as our dear friend Catmandu says, "one fine day".