Rosacea is actually an enigmatic condition. It's response to Erythromycin leads many researchers to believe it is infectious/bacterial in origin. It is not caused by alcohol consumption. http://www.mayoclinic.com/health/rosacea/DS00308
Some ethnicities do infact react to alcohol with swelling/puffiness and redness in localized areas. But, allergic reactions are typically mainfested systemically - all over, not localized as the original poster describes. I would just see a doctor. This may be a vital parte of their medical history and the precaution agains Sulfa drugs is warranted.
That is my opinon, but I'm just a doctor.