The teenage son of a Metropolitan Opera singer was fatally stabbed a few blocks from Elmhurst Hospital in Queens on Monday night during a confrontation with a gang of ten thugs believed to part of the Latin Kings gang. Nicholas Donaldi-Subero, 18, had gone to Queens from his mother's Upper East Side apartment to pick up his date; around 6 p.m.—about a block away from the 82nd Street-Jackson Heights 7 station—he was approached by the teen gang, who believed him responsible for a recent stabbing of one of their own. Donaldi-Subero's family deny it, but police say he was a member of rival gang, ABK, Always Banging Kings, and he was arrested three times in the past six months. His mother, alto Maria Donaldi, tells the Daily News, "he was the sweetest kid. I don't know about gang affiliation. Kids can be sneaky, but I'm the last to know."