Friend assaulted, unsure how to help her?

Ok, today a friend asked me for advice, i told her she can tell me anything, then she told me that she was touched inappropriately as we went into detail she tells me that he left her and now wants to be friends again. She doesn't want to be friends because she feels violated and hurt, the thing is i know the guy who did it too, and i wouldn't put it past him to do something like this, I'm unsure myself what to do here, i know it wast just him creeping up on her and grabbing her, they must have been together. I'm trying to figure out if it was a spur of the moment thing where he thought it was OK when it never is, or if it was him trying to show control. I'll post more details when i find out, as of now just post your opinions on what she should do.