We have been critical of PF for stalling the thing, but as RF4 has pointed out he was trying for a couple minutes to stay right side up with the a/c seemingly not responding to left stick.
A couple weeks ago I got a ride in the back seat of a Romanian Lark glider with a long thin wing. Thermaling the beast past 30° bank found me with the stick in the opposite rear corner.
Had to unload a bit to get some more aileron authority. Many gliders lose aileron authority before they stall from a steep bank in a thermal and I am at a loss that an experienced glider pilot would not have been familiar with this.
As mentioned many times before the transition from an apparent overspeed problem to a stall problem was not recognised.