A few points to consider for everyone guessing at the motivations/mindset of the guy and the severity of the fondling.
1. I see a lot of people saying "he was drunk, people do a lot of stupid things while drunk". Putting aside for one second that "people do a lot of stupid things while drunk" isn't actually a legal or ethical defense for anything, you need to keep in mind that he remembered the event well enough to detail how long it went on ("just" a few minutes) and what exactly took place ("just" fondling, no intercourse). He wasn't in the "OMG I woke up with a tattoo I don't remember getting" state of inebriation. When you're offering up specific details about what you did and didn't do and how long you did it for, you're demonstrating a clarity of awareness and memory that a lot of people would be envious of when they're sober. So it's a fairly safe assumption that he wasn't all that drunk. Drunk enough to lose his inhibitions perhaps. But not drunk enough that he wasn't aware of what he was doing, or the significance of what he was doing (stopped prior to intercourse).
2. I also see a lot of people wondering at his state of mind (he was in love!), her state of mind (she secretly wanted it!), and just exactly what it was he did in those few minutes. The only things we know for sure are he stopped short of actual intercourse, and his friend was completely disgusted. His friend, who he chose to confide this in, was completely disgusted, and rattled, and conflicted. So I'm guessing he didn't gently stroke her cheek and whisper "I love you" into her ear. We don't know what the OP's threshold for disgust is, but the fact he's talking about it in an internet forum and not at a police station suggest he's not a complete teetotaler. As to his motivation and her motivation? We know he liked her for a long time and wanted more. And we know he waited until she was helpless and unconcious before making a move. So hypothesizing that she might have secretly wanted it seems a little thin on the ground. It's possible the friend is simply an utter coward and this was the only way he COULD make his move, but utter cowards aren't usually in the business of sexually fondling women who might wake up at any moment. The safest and most rational assumption, based on the information provided by the OP, is that he wanted her, and his feelings were not reciprocated. I'm not sure about you, but when a woman who has shown no interest in my sexually gets drunk in my presence, I don't consider that implicit consent for me to start fondling her.
3. It's not THAT bad. At least he didn't RAPE her. Is this the cut off point for "bad" then? Anything before rape is hand waved as hilarious hi-jinx while drunk? Genital fondling is all-go now? Daddy, a strange man touched me in the park! Oh my god...were you raped? No, he only fondled my genitals for a few mintues. Oh, that's alright then. He was probably drunk! Can we readjust the bar for socially appropriate behavior to such a place where "genital fondling of helpless people who thought they could trust you" is unacceptable? That seems reasonable to me.
4. Stop trying to polarize the argument. Yes, there are idiots in here suggesting Mr. Fondler be taken to prison and raped to death. That is, indeed, completely ridiculous. There are also people suggesting the girl "asked for it" by getting drunk, is a ***** for "leading her friend on" (and don't we all LOVE to see bitches get their comeuppance, eh? Eh!?), and that anyone complaining about a little genital fondling of an unconcious woman is a hyper prude or a furious female. So there are idiots on both side of the equation. No, the Fondling Friend is not worse than Stalin. No, what he did was not "okay" in the slightest. No, he doesn't need to be immediately registered as a sex offender. No, the decision as to whether or not he gets registered as a sex offender does not lie with the OP, and whether he thinks the Fondling Friend is a good dude. The GIRL needs to be told, and the GIRL needs to decide just how bad the actions of the fondling friend were. It's her RIGHT to know that she was molested while sleeping, and it's her RIGHT to decide what that means to her. Maybe she DOES like the guy, and won't care. It's POSSIBLE. It's also possible she'll feel that she was sexually assaulted. It's her decision though. Hers, and hers alone.