Honestly, there’s not much they can do now since your dog is already been inficticated. The true danger of parvo is dehydration and malnutrition, so that’s what the vet will focus on. Mostly the dog will be pumped with IV fluids containing vitamins, sugar, and potassium. This can be done at home, if you’re up for it, but most of the time hospitalization is required.
In some cases, the vet may also inject your dog with some sort of anti-nausea medication to help prevent anymore regurgitation.
Once a dog can finally begin keeping his food and fluids down, IV’s are gradually reduced. Very bland food is offered. Many times, a vet will also administer antibiotics to help ward off secondary infection, because the dog’s immune system will be severely weak from the experience.
Take care. I am sorry for your dog.