A quality breeder, one who cares about his/her reputation will either split or fully pay the cost for treatment. Parvo is completely treatable, but it requires dedication to the cause. There can be a lot of ups and downs with it, but most pups make a full recovery.
I had an old English mastiff as a child who came to us from the breeder with Parvo. Sight unseen, they called our vet, explained who they were and ordered the vet to bill them for any costs incurred for the pup’s treatment. He lived a very healthy, happy 11 years with no recurrence, but it took almost 9 months for him to fully recover.
IV fluids are often the only recourse, as you can’t force the little guy to eat or drink. I personally would not give the dog back to the breeder, as they’ll likely let the dog die if they didn’t care enough to check it for Parvo when they adopted it out. If you’re not completely attached, some SPCA branches, HSUS, and even some very humanitarian vets will take the pup off your hands and see it to better health.
You have options. If you’re a soft-hearted person, you can ensure the pup sees better health if you do some research.
He’s at the vet and on an IV. My wife was upset when they put in the catheder. The tech had problems so it was a little rough on him.
The worst part is it’s preventable.