Bottle feeding my foster kitties.

[Minimalist]

I can't believe that any competent vet would look at those symptoms and not think parvo.

https://en.wikipedia.org/wiki/Feline_panleukopenia

The virus primarily attacks the lining of the gastrointestinal tract, causing internal ulceration and, ultimately, total sloughing of the intestinal epithelium. This results in profuse and usually bloody diarrhea, severe dehydration, malnutrition, anemia, and often death.

Thus one can only hope that he ruled parvo out and is treating them for something else.  As the article notes, untreated parvo can kill them in 24 hours so if you took them in on Friday and they are still alive that is a very good sign.