In the documentary about the boy (David Coombs) who wants to ski the line, Couloir Polichinelle, at LeGrave thatDoug Coombs died skiing, there is a scene where Glenn is teaching him the windshield wiper turn, the ultimate control turn for steeps, an old school turn, but still the most important tool in the box in certain situations, like skiing that couloir. speaking of Glenn as a teacher; he rules.
Pretty sure you are talking about The Edge of Never,and the kid is Kye Petersen ( 15 years old at the time of the film, son of Trevor. Petersen, who was killed in an avy in Chamonix. Doug Cooms does appear briefly at the top of the tram. Be glad to share my copy if you haven't seen it.