technically we don't know if he raped her or not, he proberly didn't actually.
Regretting having sex while being drunk the day after is not the same as rape.
He dragged her from the room they were drinking in to a motel and her friend was there too, if she had resisted someone would have acted, but she didn't, and neither of them knows if she agreed to it or not and so far we don't either.
reason i say he properly didn't rape her is because she didn't struggle on the way to a motel, remember they were both drunk, afterwards yes she is angry at him and she regret what happened and she doesn't seem like the type to just have sex with a random dude, but people do many crazy things when they are drunk, it would have been different if he had forced or encouraged her to drink.
That is just my opnion of course you could be right and she was raped but i rather get the feeling that this was a foolish act between 2 way to drunk for their own good.
THE BOY TECHNICALLY RAPED HER!!!!