Really what she needs is brain rest. You would be taking her out of school and postponing her education. She could likely make up the classes she misses over a summer or something.

Think about it this way: if she had cancer and couldn't stand up because of chemo side effects, would you still try to make her pass Intro to Chemistry? No, you would wait until the chemo was done and then try to catch up on what she missed.

This is the same thing, only the damage is invisible to you.