Pepper, you are going through a terrible crisis right now, and probably doubting whether you are making the right decision for Bourbon. Which ever way you go is a risk, you have tried the other way, who knows maybe the holistic will give him more time to have quality in his life. I still think I would go the way you are going at least it wouldn't be invasive and I have heard good things about it. No matter what the Vets say, it is your decision in the long run to make, you are the one who loves him so much.
Jackie