If it wasn't a dream, then this girl has a serious alcohol problem. Blacking out and not remembering what happens could lead to seriously severe consequences. Imagine if she had been on a date with some not so reputable guy.
@FredFriendly eh overestimating your tolerance happens and it doesn’t necessarily mean she has a serious problem. Sure it’s potentially dangerous but she likely wouldn’t have drunk this much if she wasn’t with someone she’s comfortable with, and making such a mistake is not at all the same as being an alcoholic.