Motocross dad Thurman Maynard, former undercover cop Sarah Olsen and Pete Frates, who helped launch the "Ice Bucket Challenge," share their stories of hope, treatment and ongoing battles with ALS. WATCH NIGHTLINE EPISODES: https://abc.go.com/shows/nightline ALSO AVAILABLE ON HULU: https://hulu.tv/2wSmSrZ #Nightline #ALS #AmyotrophicLateralSclerosis #IceBucketChallenge