Kidney Disease in cat or something else?

[MnM]

I'm hoping for some help here! I'm currently living in Bangkok with my two 12.5 year old cats. The vets here are ok...hard to understand and I'm just wanting to be sure that I'm not missing something. Recently my boy, Mikey, had a urinary tract obstruction and then infection. The doc used the catheter to push back the plug, took blood, gave sub-Q fluids, and meds. This was Monday night. The blood tests came back with BUN at 26 and Creatinine at 2.14-doc said renal failure. Continued sub-Q fluids, pill for bladder lining, pill for anti-inflammatory and an antibiotic. Since then started him on phosphorus meds and had to get an injection for stomach acid reduction. Doc had him eating Hill's C/D then switched Saturday morning to K/D (though that was when he was vomiting and we brought him in for the stomach acid, so didn't really get much of it in). Took blood again and BUN is up to 31 and Creatinine up to 2.41. Back in June of 2008 his BUN was at 26 and his Creatinine was at 1.0.
Does Mikey have renal failure and kidney disease? Is there any chance, any at all, that he could come back from this and live to the ripe old age of 20something? Is there something more I can do? I feel like my heart is breaking...any ideas or info would be appreciated.