Please help our dog Pac

Pac was hit by a car and the saddest part was they left him there to die if it wasn’t for a neighbor we wouldn’t of know he was laying injured on the road. We took him to the emergency vet and where told they needed to keep him for observation there are no broken bones but they did find fluids around his lungs and and belly. They did a poke test on his belly and found blood they aren’t sure where the blood is coming from so he will be staying in the hospital for the next few days for observation. There is a chance that he might need surgery but we are keeping our fingers crossed that he comes it doesn’t have to get to that. So far our vet bill is at $750 and this isn’t counting any additional cost of services that are needed for his care. Please please help us if we can’t come up with the money we would have to take him home without the proper care and then he’ll have a 50/50 chance of survival.