Gee. How kind. With a little luck she can wake-up to the fact that she cannot move and will have to rot in bed until she dies.
She can always make her own choice to die of thirst and starvation, but at least it's her decision and not yours.
But that's kind of the point, eh?
If she is truly vegetative, this drug will not help her. But most importantly, you see a story that says theoretically a thing could happen, and you glom right onto it. Well, theoretically she could be in great shape to begin rehab if theis drug works, and regain most of her function. We just don't know, and the potential harm in withholding the treatment is far greater than the greatest possible downsides from administering it.
Yeah, paralyzed people don't really want to live, or be professors of physics and mathematics at Cambridge or anything. :p