The latest reports indicates its not a kidney disease, They discovered the prostate is suddenly enlarged and is somhow blocking the flow to the kidneys causing the problems.
If this is correct I guess he could keep the kidney specialist for a week or two.
If a kidney specialist is investigating and is confused by the symptoms, I dont understand why he hasn't determined that obviously your father's kidneys are failing. working at 25% is not good,,,,, if he drops anymore he may need dialysis. High blood pressure is a kidney killer. Your dad needs to find another nephrologist quick, in my opinion.
For more information on kidney diseases, so you can inform your Dad there is a federal website that list and explains kidney diseases from A to Z. Go to http://digestive.niddk.nih.gov. The website is combined with digestive diseases should you develop questions whether your Dad's digestion and kidneys are related. When you go to the home page, look to your left and you will see blue bars. On one bar it says Kidney Diseases, click and schroll up and down the A to Z list until you find the kidney disorder you want.
Harrald