See a vet if you haven't-perhaps it's not the end of the line
And yes-I'd let your dog have what he wants in small amounts so long as his tummy doesn't get upset. It's not uncommon to take a dog for a walk to his favorite place and then to McDonalds for a double cheeseburger before his last trip to the vet to help him cross rainbow bridge.
For future reference, chips and junk aren't good for dogs, but their is nothing wrong with feeding your dog human food. Mine gets one meal a day that's our food, and he'd have all human food if I could get my mind around balancing it. Definitely let your dog have some food he loves-and when you have healed and have another dog-let him have some human food too
I'm sorry to hear your dog is going to leave you soon. He had a good home and was loved, and that's all they ask of us

*HUGS*