WOW!!!! the 2 twists that I have come out of inverted flat spins easy ,just release the sticks roll it on its top and fly it away. Both my planes will flat spin upside down or rightside up.IMO I would say that your friend had a CG aft prob.
P.S. if they get another one make sure they put some lightweight flying wires on it.
Happy Landings C.W.