I know you said she won't accept money, but what about a gift card for movie tickets or video rental, or a gift card for a coffee shop that she likes? When I was in college, I loved receiving gift cards for evenings out or a movie rental, since I didn't have a lot of money for entertainment.
Or - treat her to a girls' night/girls' day out once your child is well. Plan on buying her lunch or dinner, or pay for a manicure for her. The rest of the time, you can do something inexpensive, like window shopping or watching favorite "chick flicks."