She's tried many different kinds of dog food (and cat food!) both dry and wet. Everything from bil-jac to blue buff. The dog refuses to eat. They need to get it on a constant schedule, because the dog has diabetes. They can't give the dog insulin until its eating properly.
She'll go days without eating, so they have resorted to giving the dog human food. But after a few days she won't eat it anymore. She's tried peanut butter, cottage cheese, cheese sticks, chef boyardee, quinoa and chicken, veggies, etc.
The dog is losing weight quickly, and I'm just looking for suggestions before they have to put the dog down.
Have they talked to their vet about this? Normally, with a picky dog, I suggest scheduled feedings where the food goes down for a certain amount of time (maybe 10 minutes), and if the dog doesn't eat, you pick up the bowl, and they don't get food until the next scheduled meal time. However, given the medical issues involved here, I personally would consult my vet asap.
Yes, they go to the vet fairly regularly. They have done everything the vet has suggested to get the dog to eat, but it just doesn't want to. If they take away the dog food if the dog doesn't eat, the dog will not eat for a few days. My co-worker won't let the dog starve for that long, and gives it people food just so it doesn't pass out.
The dog won't starve itself to death. How long has the people food pattern been going on? Is it possible that the dog has been trained (or trained your friend!) that if he doesn't eat the dog food, eventually he will get people food? I would try to just set out a very good dog food and see how long it takes him to get hungry enough to eat it. If he passes out, something is really really wrong with the dog to supress a survival instinct.
With a diabetic dog they may need to cut out all carbohydrate-type food (grain and veggie free). A raw meat and fats diet might be the ticket here to get the dog eating something healthy. And, who knows, may even clear up the diabetic issues.
Shouldn't try to give the dog cat food either. Cats have a higher need for minerals which, if i remember correctly, can approach toxic levels for dogs that eat cat food.
If the vet doesn't have any better ideas I'd ask another vet just in case.