Hey Genie!
Sorry to hear the news about Cookie, my daughter was lookin over my shoulder when I was reading your post. She said that the Dr. at the Emergency Center does the Portosystemic shunt operation all the time.
It may not hurt to have them look over Cookie's test results and give you a second opinion on everything. It's your decision tho, maybe he doesn't need any more poking and prodding right now.
You're right tho about just enjoying the time you have with him, these lil guys are so fragile, even without health issues things happen all the time and they could just be gone. So we have to enjoy every second we have with them.
This doesn't need to apply just to our furbabies either, we should take this philosophy to all of our loved ones.