I recommend you making own beef and pork broth with carrots, parsley roots. I'm giving only the broth with vegetables and small portion of pasta for my 14 y.o. dog and she's having a lot better blood results. Of course besides drips.
May I say it is better for you dog to eat anything than nothing. If it is refusing kidney diet consistently offer anything the it will eat and call or see you vet to get him on a appetite stimulant and a med for nausea which will help you pet to feel better and hopefully help them transfer to a good kidney diet