Why would he have to be college age? He could have been an authority figure the cafe guy would have trusted. "Friend" could have meant..."friend of the family", "friend as in boss type figure", "friend as in apt. manager", etc. I would think Cafe guy would have least trusted a college age male student to safely take care of a young, intoxicated female. If he cared about her safety enough to walk her home in the first place...why would he hand her to a guy that might only want to take advantage of her being in that state?
The authority figure example is plausible, but unlikely. It's been a while since I've been on the bar scene, but really, truly in that area of downtown Madison, and at the bars Kelly went to (SSB and Lava) it's not a mixed age group. Any "older" man (i.e. 30's and up) is viewed VERY suspiciously and most people assume they're there to hit on younger girls. Older men are persona non grata in most of those bars - women don't talk to them and young men ignore or make fun of them.