OK. How old is he?
Acupuncture and chinese herbs have proven to give positive results when treating kidney issues.
See if there is a vet close to you here CHI certified
This one, if anywhere near you appears to have the most certification by CHI:
Joanna Ka Wai Lee, DVM, CVA
Specialty: Small Animal, ExoticKent, DA11 8RD, UNITED KINGDOMTele: +44 7990513583