[anonymous]

I think it would be best to ask the veterinarian that is treating your dog, dogs that have kidney disease tend to be nauseous. Food supplements often interact with prescription meds.
Your dog has a history of medical problems, plus he is a senior. Coconut oil is high in fat and calorie content. The younger dog may tolerate it, but the older one, not so much.
Hope this helps:

Coconut Oil for Pets?