In reply to waggers:
I hope you're doing okay. My sister suffered serious head injuries in a horse riding accident a few years ago. It can take weeks at the very least for the swelling to go down, and much longer for the patient to be in a stable enough condition to be conscious. Rushing the process can cause further damage. The best thing you can do is be as supportive as you can for her and her family on the long and uncertain road to recovery and rehabilitation, and look after yourself in the meantime. Don't lose hope.
She's lucky to be in Frenchay, my sister got flown straight off the hill to there. The staff (doctors, nurses, cleaners, everyone) are amazing - true lifesavers.
In some ways the worst part is the uncertainty. Hang on in there. The outcome isn't necessarily as bad as it feels that it might be right now.