As a bartender (I'm not one at the moment but once a bartender always a bartender, right?) I'd say the C&C is a typical "African American Male" drink. I use quotes because, duh! Stereotype. But based on this little clue we know he's African American. Wee!
The Absolut Citron could mean he's gay. No, the fact he likes a lemon flavor to his drinks means nothing, except he likes lemon. It's the brand name that says, "gay." A straight guy would typically go for vodka. A gay guy would typically (as in, stereotypically) go for the trendy brand name "Citron" vodka.
But I'm sticking to my theory that he lives in a "gay" area of Boston because it's trendy but he himself is not gay. He's maybe been socialized in the gay culture there, but not himself gay. Maybe he's what they're calling a "Stag-hag" these days. A straight guy that hangs out with gay guy friends because it's trendy & a great way to meet all the "fag-hags", the straight women that hang out with gay guys.