Would it maybe be a corkscrew dive? Quite a few leafs tend to spin down in a corkscrew as they float to the ground. Could he not just be in a corkscrew dive to keep control of the aircraft speed? I do this type of move in the K4 quite often now, it lets me bleed off speed at a controlled rate with my rudder and I can end up on a lower cons six at a manageable speed to take that all important tatter shot.
It also has the affect of not giving away your true angle of attack, because you aren't diving right in on the con. I dunno if this dive has a name, it's just something I picked up on my own and seems to work but seems like "falling Leaf" would be an appropriate name for it.