From what I have read she had suffered some serious concussions and was struggling with the after effects
I have been following this story with interest (I grew up with someone who had a serious TBI).
Seems she had been fine, if pressured, until the head injury. Following that, she had continual, major symptoms. Constant headaches. Sensitivity to light, noises. Flashing lights in her eyes, inability to concentrate. Physical weakness. Mood swings.
All of these are typical effects of a TBI.
In someone so driven and riding (literally) on the edge, this would have been devastating. Poor girl, poor parents. What a loss to the world.