It makes me ill to hear what happened to your grandmother. Just physically ill.
It seems impossible that the person who drove the car and participated in at least the abduction of the woman out into the country couldn't have been charged as an accessory to the crime. I don't understand this at all. Do you know what the reasoning was behind not charging him with anything?
I am so sorry that this happened to your grandmother. It's horrific. I hope she was able to recover from it, and I hope the rapist's sentence is long.