This is so sad. I don't know what I'd do if I had to choose to put my cat down!
I mean, obviously it would be for the best if I did, but to actually choose to kill your cat would be horrible. I suppose I would have to, in the end, but it would hurt every step of the way, i'm sure.
I have a pretty big imagination, but even with it I dont' think I could get a whiff of what you're feeling unless it actually happened to me. Which I am glad it hasn't, but I suppose that if you are a person with pets in your life that you will inevitably have to go through with the death of a beloved family member.

I'll be praying for you and Zsa-Zsa with all my heart, and I truly do hope that things work out for the better.