If You Want to be a Rock Star, Just Ask

Sometimes, a simple question is all it takes to achieve a dream. Brian McCauley is living proof. Legally blind since birth, the result of retinopathy of prematurity, the 22-year-old Tewksbury, Mass., resident recently lived out every rock and roll head banger’s fantasy: singing onstage with the artist you’ve long worshipped through wall posters, CD purchases…