So sorry to hear about your pup. I used to work at an animal hospital and our area has had very high instances of it, so I've seen many pups come in with it. There's not much that can be done other than what you're doing. IV fluids and meds are the pups best bet, but it is a terrible illness and sometimes they just can't make it through. I'll be keeping your pup in my thoughts. I don't really have much to add as far as treatment, but please be aware that it wouldn't be a good idea to get another puppy that is unvaccinated against parvo for a while. I would wait for over a year before I got another unvaccinated dog as parvo is shed by the infected dog and can live on surface that have not been disinfected for about a year, so while a house may be disinfected if anything is missed then the virus could still be present. Outside (ie: the soil) would also have to be decontaminated, so it's best to wait it out to make sure the virus is gone before getting another unvaccinated animal. Puppies aren't fully vaccinated from the virus until they have received series of boosters which is usually complete between four months and 6 months old. Like I said, I hope the best for your pup. I've seen many pups pull through with good care.