Is this rape?

First of all I just want to clarify that I'm not the one who experienced this, it happened between 2 of my fiancés friends and I'm only asking out of concern for my safety. Also, I dont have all the details.

Okay, so one night my fiancés friends (lets call them Luke and Becky) were drinking at Lukes apartment. They both got drunk, but Luke was less drunk than Becky. Becky has no memory of what happened from when they got drunk, until the time where she came to and saw that she was on top of Luke and they were having sex.

Now, Luke and Becky have gotten drunk together lots of times before and nothing ever happened. Becky came to trust Luke that he wouldnt do anything like that. But they also had previously talked about how if something did happen while drunk, they wouldnt make a big deal out of it. Becky is saying it was rape and Luke hasnt said anything on the subject.

What do you think?