If they got the puppy from a good breeder the breeder may take him back. I would ask about it and if it is papered and they do have a contract with the breeder then the breeder does have first rights if they can no longer care for the puppy. Also they might not be aware of this either. It is really sad to see anyone give up an animal. I hope he does find a good loving home and stays there for the rest of his days.