ok, if he's that heavy of a coffee drinker, then he's most likely a heavy smoker. I'm guessing this is a smoke-free campus, no? When a heavy smoker abstains from smoking for many hours, the reserved nicotine in the system begins pumping.
I had a volunteer working for me last year everyday for a month. The nicest older lady you'd ever want to meet. But she had this "odor" about her. Not dirty, not BO, not cigarette smoke. Just an odd smell - & I could smell it as soon as I walked in the room. I did a little research on it and sure enough, that's what I discovered.
I watched her one day from the window as she walked out. As soon as she got into her car, she lit up a cig.
It's a thought.