Dog diagnosed with kidney disease - diet help

Recently, my SO’s 7 year old dog was diagnosed with kidney disease. The vet gave us a prescription to give him once a day and put him on prescription food. Didn’t give us much of an answer for his future besides, “It could be 6 months or 6 years” (FWIW due to an early life accident, his kidneys have always been weak )

The pills are Benzaepril (10mg/day) and the food is Hill’s Kidney Care

A couple of things going on, and he started this regime in June:

He is constantly whining for food. We were doing a cup and a half twice a day, then recently have added an extra half cup total. From the moment he wakes up, all day until he falls asleep he wants food. He has never been a beggar. The poor boy is probably starving. In the last couple of days, we are adding a small portion later in the evening to hold him through the night. Is it because the food has less protein than he’s used to? He ate Hill’s Sensitive Stomach before switching to Kidney Care

We used to give him raw hide bones, but he can’t have them anymore due to the amount of sodium. We have been letting him have a handful of green beans or so as a treat to try to tie him over... the vet suggested this. It is not helping. Does anyone have any suggestion on what we can be doing differently to prevent the constant whining? It’s not the whining that bothers me so much as knowing he is constantly hungry

Another issue we have had are spots on his belly. At first we thought it might be ringworm, because he had it about 3 years ago, but it’s not ringworm. They are almost like sores. They slowed down for a short period of time after we started the medication but they are still showing up. I typically make a coconut oil/tea tree oil combo and apply it, and they end up drying up and healing. Unfortunately we have yet to figure out the issue

I’m just stumped on where they are coming from. The Vet told us “biting flies” but I just don’t find that to be remotely close to the issue.

Mainly looking for suggestions from people who have had experience with this. Treat suggestions to hold him through the day (can’t be high in protein...), suggestions as to what the rash/marks on his skin are also welcome

Thanks in advance