Jake's sick - may have kidney disease

Jake is my orange tabby...he'll be 15 in August. We lost his sis Jessie 3 yrs ago to KD and am trying to keep Jake as happy and healthy as possible. Jake has been controlling Urinary Tract Problems for a couple of years. Over the past couple of months he's been vomiting (basically bile) just about every day-eats little spread throughout the day-has lost a couple of #'s.

I have changed vets (because Jessie's did nothing but watch her die). This vet is more aggressive and explains options. He is suggesting a blood pressure test and an ultrasound ($$$) which will see into the kidneys as well as other areas of the abdomen. He will learn more from the ultrasound but has already ruled out any infection. An X-ray showed that one kidney is rounded and deformed. Blood and urine tests and urine culture already completed - no bacterial infection but blood and proteins are leaking into the urine. Instead of the ultrasound a urine test for creotine(?SP?) may yield enough info but maybe not. I want to do everything necessary but not excessive.

I would greatly appreciate any input from you kind folks. Do any of you provide at home fluid injections to your dear ones with kidney disease?