I know it is okay for a dog to go a couple days without eating but that wouldn't be going on here either.
I've never had that problem with Ellie. She eats whatever.
I don't really know what to say except if it were me, I'd do what he wants as long as their is some nutritional value to it. I'd homecook (with supplements) and keep switching it up. I have a lot of sympathy for the dogs who get bored with the same food and nobody can prove that they don't get tired of it...