It's definitely hard when kids have a fever to get them to eat! I feel for you. I wouldn't push him too much, but a few things I have found that work, Chicken broth. I will make a couple cups and put it in a sippy cup so my son can drink that instead of juice. It gives a little protein and hydration. Toast, see if you can put something on it. My son likes nutella and he feels like he is getting something really special, and I have checked out the label, it has sugar but other than that is no worse than peanut butter. A little goes a long way.
My son loves pasta and I think would eat it regardless of how he feels. Maybe try to stick to his favorites!
Good Luck!