Definitely get something for the nausea. Compazine, zofran, if she can not swallow get tigan suppositories, they really!!! help.
As for the food, try liquids, broth, gatoraid, melted jello, ice cream etc. Have her take the anti nausea med first then after 30 min a pain med then later the food.
The diarrhea can be controlled with imodium or if needed prescrip lomotil
Good luck-this to shall pass with time.
Cindy