If your dog has not drunk anything for over 24 hours, I would get to a vet asap. He could be seriously dehydrated and need IV or subcutaneous fluids at the very least. If he was only vomiting I would try a 24 hour fast and then small amounts of boiled chicken and rice, but at his age and being unable to hold down fluids I think you need to see the vet. Good luck.
Thanks deadgamegrrl! I forgot to add that he was drinking a lot of water before he stopped.
His stomach may just hurt too much at this point for him to want to put anything in it. The vet can give him an anti-nausea shot if this is the case. Let us know what happens!