Maybe he was in the same inebriated state as her?
She was not comatose. Maybe she is a vindictive person? I  believe this type of "assault"  accusation is actually about bullying and persecuting  men.
Men can be tarred and feathered by a female at any time in this society which is precisely what these feminist agitators demand. Look at the Gian Ghomeshi case. All the witnesses all lied and colluded with each other and they still screamed for his conviction. 
Why is she the victim here and he is the predator. 
Sounds like two drunk college people to me. Certainly not an assault by any standards.