Filmmaker Kirsten Johnson lost her mother to Alzheimer's in 2007, now her father has dementia, and is disappearing before her eyes. As Kirsten struggles with grief over the inevitable loss of her father, she finds ways to celebrate his life and get closer to him. She tells Anderson it's never too late to get to know someone you love more deeply even after they are gone.To learn more about how CNN protects listener privacy, visit cnn.com/privacy