If she was that drunk that she did not know what was happening, then she was unable to give consent and it is rape. Is that what she is saying? That she has no memory of it and did not make a choice? Or is she suggesting that someone did something to her drink and that's why she doesn't know how or why?
Or is it that she had a few drinks and made a choice which she was in control of but says that she only did it because she'd had a drink?
The issue of consent and massive quantities of alcohol is a big one. If she was so drunk that she didn't understand what she was doing, did she have capacity to consent.
However, on the issue of alcohol alone, it is a dis inhibitor, not a personality changer. You couldn't choose to do anything that it is against your nature to do. So you wouldn't, for example, steal if you were totally morally against stealing. you wouldn't beat someone up if the core of you was pacifist. etc etc.
But that is about your choices and not things that were done to you.
So it really depends what happened, tbh.