Prognosis for a Puppy with Parvo?

My Labrador puppy is about 8 and a half weeks old. We picked him up on Sunday, and that night around 1 AM he began throwing up white froth and was making noises as though in pain. We took him to the vet the next morning when it opened and found out it was parvo, and the vet immediately put him into intensive care. He has had two vaccinations, one when he was about 4-6 weeks and one in the last week. Tuesday he was doing a lot better, but this morning, Wednesday, it has deteriorated slightly. We were told it would fluctuate, that it would get worse before it gets better. He has not had any bloody stool, he eats and drinks, but not a lot. He's hooked up to an IV, and he's still with the vet. What are his chances? We're hoping and praying that hell make it through.