Hi. I'm so sorry and you must be so worried.
I'm no expert, but I hope I can tell you something to temporarily help until you see the vet.
Try to have him lick yogurt off your finger and drink a 50/50 mix of Gatorade. The live bacteria in yogurt could help a little the same way it helps humans, at least until you see a vet. You have to keep him hydrated and warm.
I'll pray for your little guy.
Take care.