From Grand Theft Wiki

Roy Zito is the thirty-five year old underboss of the Gambetti Family, a role he took over when Sammy Bottino went into hiding. Zito runs a number of Gambetti owned dry cleaners throughout Liberty City that specialize in removing forensic evidence. Fiercely loyal to his Don; rumor has it that when Jon Gravelli was facing kidney failure Zito offered him his kidney. Gravelli refused the offer but Zito countered by removing his own kidney with a knife and delivering it to Gravelli in a bucket of ice. He is most likely to be the successor to Gravelli, unless Bottino comes out of hiding to claim his throne, which would inevitably spark in an internal war. Tony Prince mentions that he knows from "personal experience" that Roy Zito is a closet homosexual, although if asked he would say Tony spiked his drink.