I feel really sorry for your friend. I think that she should go to a doctor for an exam and a rape kit if that's possible at this stage. I agree that he is probably a predator and might do this again. I also agree that she is probably in shock about what happened.
The same thing happened to a friend. She didn't go to the authorities because she felt ashamed and embarrassed and partly responsible. She also couldn't remember the details. She later regretted not reporting it. She had a really hard time for a long time.
