The video is almost 40 minutes long. I won’t bother to see if there is anything related to the topic, other than the name “Rogallo”.
Rogallo type rescue parachutes sell well and are available in several brands. It seems interesting to me to try to exploit their high coefficients and their resulting low sink rate. We could make reeling tether-aligned kites with very high traction (Cd of 2-3, Ct of 3-4).