The doctors gave his father just a few days to live. The coronavirus had infiltrated Marc Lewitinn’s lungs, leaving them no choice but to place him on a ventilator. The litany of health issues the 74-year-old grandfather had endured in recent years — including cancer and a debilitating stroke — would make it nearly impossible for him to fight off COVID-19, the Weill Cornell Medicine doctors told his son Albert in April2020. It was time to think about end-of-life care. But Lewitinn’s family knew better. “You don’t know my father,” Albert Lewitinn told them. The Cliffside Park man would defy tho…