Sometimes these things really linger. 3-4 days happens with a number of viruses, sometimes as much as a week.
Dehydration is the main problem - the temp isn't that high. I wouldn't medicate that fever unless he's got a bad headache. A cool cloth can be comforting.
For fluids, start slowly after the vomiting (at least 3 hours after last vomit), and just give fluids in small doses. Water, popsicles, ice chips. Ginger ale (no other soda) stirred so it's flat can help - it's the ginger, not the carbonation that helps. Keeping his sugar level up can help as well. You can graduate to pedialyte. Try not to give anything with a lot of dyes in it, although a little jello might be okay. Really wait in between though - at least one hour to be sure things stay down.
Then you can give some saltines or oyster crackers.
Don't be surprised if this moves downward and he gets diarrhea. That's very common. Do you know about the BRAT diet? Bananas, rice, applesauce, toast. No dairy.