Martin Short had seen more “death and tragedy” than any of his friends by the age of 20. The 74-year-old actor was just 12 when his older brother David was killed in a car accident, his mother died following a battle with cancer just a few years later and his dad passed away in 1969 complications from a stroke but has no idea why that sort of trauma didn’t “screw [him] up” in the long run. He told The Hollywood Reporter: “All I know is that you only know your own life. At 20, I knew things about life and death and tragedy and loss that none of my friends knew about. I don’t know why this didn’…