My guess is the authorities are going to investigate to see of he is guilty of neglect, abuse and abandonment of the dog which would allow them to take the dog away from him to give to the rescuers. This guy may regret fighting for the dog because he might end up being prosecuted.
My guess is the owner will be charged criminally with animal cruelty and abandonment, then be offered a plea deal if he agreed to surrender the dog, pay for vet fees, and agree not to have another dog.