Dear Sir,
a chronically damaged, hydronephrotic
kidney with just 12ml /min function cannot be managed with medicines to improve kidney function. The good news is that the other kidney is doing the job of both the kidneys quite well as of now. If the damaged kidney is not causing any problems like repeated infections then the urologist would not want to unnecessarily remove it. Keep following up with the urologist as per his directions and hopefully everything will work out in the long run.