Definitely, do not give anything else intravenously.
You will have to focus on the pedialyte, gatorade, or even adding some canned tuna juice to his water (change frequently as it will spoil) to help encourage water intake.
To help the stomach, you can give a 1/2 tablet of a over the counter Pepcid A.C. antacid 10mg regular strength. So, you are giving 5mg.
I assume the vet sent you home with some medications as well.
If not, ask for Cerenia, a once a day strong anti-vomiting drug, than can be given along with the Pepcid A.C.
If diarrhea, ask for metronidazole.
You can even give him a teaspoon or two of pancake syrup or karo syrup. It will give some energy.
We used to believe that we would not feed them in the face of vomiting when they have parvo. Now, it is believed even if vomiting, we still want them to eat some. This is not true in any other situation like having swallowed a foreign body.
Hope that information helps