intheweeds said:
Well, there's at least one more question that would need to be answered before I could give a definitive response. How drunk was he?
For example, if he was sober, that's rape. And I don't just mean that morally, (though it is), I mean he can be charged and convicted of rape in a court of law. However, you said he was also drinking, so it's not that cut and dried.
If he was just tipsy, then it's absolutely awful, a 9 on the scale, and it's squarely his fault. Just as bad as if he had been sober.
If he was genuinely drunk, then it's still pretty bad, but, it's more reasonable. He definitely shouldn't have done it, and it's still possible to recognize that an idea is bad when you're drunk, it just takes a lot more willpower to prevent yourself from doing it. A 6 or so.
However, if he was flat out smashed, well then, he has the same amount of responsibility as the girl. When people are that impaired they do things they would literally never do at any other time. You said you had an experience with a drunk girl throwing herself at you, well, the exact same thing just with a guy. Only your girlfriend wasn't sober enough to say no. That said, alcohol ultimately just lowers inhibitions, so somewhere deep down inside, he wanted to do it (though, again, equal responsibility). A 3, or maybe a 4.
Just as a note, no matter how drunk someone is, if they're the type of person you can describe as "extremely sweet and respectful towards women", then they would never do something like this.
So that's my response, you can figure out for yourself which one applies.