Dear friend, welcome to HCM!
On reading your description, I feel they have sedated her to secure a safe airway and control respiration artificially after a fractured neck vertebra as it can endanger life.
This is a therapeutic intervention.
At this age this is a serious injury and there could be a brain injury
What does CT scan
Please get guided by your treating doctors' advice.
I will need all test reports and medical condition to comment if this is a severe injury or -end-of-life situation.
Would like to help if you post more info.
Take care and please keep me informed of your progress.
I hope to have answered your query satisfactorily.