FYI Incompletes are only applicable if you are doing well in the class…I used them twice, once when I got pneumonia at the end of the semester and once when i was in a car accident.
It is probabaly too late for a regular Withdrawal (but check the school calendar).
A medical withdrawal maybe a possibility (but you would need to get a doctor involved).
Like other say, think long term. Is it better to save the GPA or same any possible credits she will get?
It is more important to have good physical and mental health rather than attending college in a linear fashion.