Robert De Niro says he was in 'disbelief' when he learned his 19-year-old grandson had died: 'It shouldn't have happened' Leandro De Niro-Rodriguez, the 19-year-old grandson of actor Robert De Niro, died of a drug overdose. He was the son of De Niro's adopted daughter. https://www.businessinsider.com/robert-de-niro-grandson-cause-of-death-disbelief-leandro-2024-2