Kidney/Liver disease and Diet

Question
My 15 year old Dachshund became a victim of tainted dog food 5 months ago. Luckily tested and treated within 1 week of becoming ill. Kidneys are damaged, on low protein NF dogfood. Now liver enzymes have come back dangerously high and he has been put on Milk Thistle, Amoxi tab 100mg and Metronidazole. My question is this, he has lost weight (5 pounds.) Every thing I read about diet stresses to heal the liver damage you must feed your pet a high quality digestible protein along with carbs and insoluble fibre but cut fat out. What exactly should I be feeding him in conjunction with the liver/kidney problem?

Answer
This is a very special case.  Any common dog diet is rich in fat to provide the essential fatty acids for skin and coat plus palatability and as a rich source of calories.  I think the best thing is to work with your vet on his diet.  Hills provides a number of specialized Science Diets and may have one that meets your dog's needs.  Your vet may also know of others.  

I don't pretend to have the knowledge to do the highly exacting task of formulating a dog diet.  I doubt many dog owners do, or even many of those on the net advocating it.  I do have years of experience with the successful feeding of commercial chows.