"There have been several touching documentaries on Alzheimer's victims," filmmaker Cynthia Banks is telling me on the phone. But she wanted to look at the people who have to look after them often for long periods of time. "My mother, Phyllis, started the ball rolling in 2015 when she phoned me for help. When I got to the hospital my dad was tied down to the bed and extremely agitated. And for the first time I watched this strong woman crying. She'd always been the most resilient in my family."