After consulting with a surgeon, internist and my regular veterinarian, we have reached the conclusion that there is nothing I can do for the Shadow Man other than supportive SQ fluids and potassium replacement (his K+ levels are low).
At first, I was at peace with this. Then I learned that there is actually a veterinary hospital in New York that has successfully treated many, many cats with ureteral stenting, and also ureteral bypass for the past 5 years. With an extremely successful postop success rate. According to one of the vets there, they have had cats die since they had this surgery, but none from kidney/surgery related issues. Shadow is a perfect candidate. They actually consider the surgery pretty minor, and will even do it in very sickly cats, but Shadow is very young and healthy and perfect. He could live another 10+ years after this minor surgery.
Except I can't afford it. So now I feel really guilty. They estimate $6-8K for the surgery and hospital stay in total, maybe as low as $5k because Shadow is so healthy and would likely be able to leave the hospital sooner. I don't have $6-8K plus travel expenses. We can't do this. I feel guilty. If his owner had oodles of cash, he would/could live a long and healthy life after stenting or bypassing this obstruction. But we can't afford that, so his life span is now unknown, but likely to be quite limited. Sucks. I almost wish I hadn't heard about this, because I was feeling OK with the idea that we were doing everything possible for Shadow, within the guidelines of keeping his quality of life as our determining factor for what we will or won't do. To know that there is a minimally invasive surgery with a permanent solution for him, that I simply cannot do for him because of my own financial status is crappy. The combination of tripling what we owed the IRS as compared to last year, and paying off all of Boo's vet bills and our spendy cruise vacation before Shadow was sick and now all of Shadow's current bills means that we are already in some credit card debt, and can't really go that much further in.
Anyway. Supportive fluids and potassium supplementation. He doesn't mind the fluids as much has he does that nasty potassium. I tasted it--smells sickly sweet, but tastes like gluey gaggy nothingness. I sure wouldn't want it smeared in my mouth twice a day. But, he forgives me a few minutes afterwards, so we are doing OK.