Dogs can become paralyzed from the bite of a tick. Can you get the dog to a vet? Check the dog carefully for ticks and if it's long haired, you may want to shave the dog. If it's tick bite paralysis, once the tick is removed, the dog will improve dramatically. If not caught, the paralysis will eventually destroy the dog's ability to breathe, and he will die.
http://www.petplace.com/dogs/tick-bite-paralysis/page1.aspx
http://www.petplace.com/dogs/tick-bite-paralysis/page1.aspx