A home-health aide and four relatives kidnapped and nearly killed an 80-year-old Brooklyn widower in an effort to trick him into handing over his legal rights, his money and his $500,000 home, authorities said yesterday. Cops on Thursday rescued decorated Army veteran Frank Maiorana, of Borough Park, from the Queens home of Saint Michael "Stacy" McKenzie, 26, sources said. "When we got to him, he was in pretty frail shape," a source said. "We don't know how much longer he'd have lived." Cops believe the crew persuaded Maiorana, who suffers from dementia, to sign over his power of attorney and...