I feel for the pilot. I have never been in a large airplanes wake in a helicopter, but a couple of times in my previous plane (a Cessna 140) I had issues with "unseen wind"
The first time was when I first bought it, and was flying it home. I was dodging some thunderstorm activities flying from Columbia CA to Bakersfield. I was following a helicopter who was reporting pretty benign conditions on his flight path, so ATC guided me along the same route. I ended up in a downdraft that knocked me from 3K to about (I found out later, 200'AGL before I was able to get out of it. Luckily it was at night and I couldn't see the ground (or houses or whatever was there). I could hear the panic in the controller voice as she tried to get me to an airport.
The other time was at my home airport. There is airline traffic out of there and I was doing T&G's on a parallel runway that had an MD-80 that take off. The "swirling wind" found it's way over my runway as I was landing and I ended up touching one wheel on the pavement, and then tipping on the side, and after firewalling the throttle, about an 50 degree bank just a few feet above the runway, wingtip almost touching the ground. That was one of the few times I actually felt like I was going to eat some dirt. Still not sure how that little C-85 had enough gumption to get me out of that situation, but I kissed that spinner when I set it down. Sometime's it's better to be lucky than good.
Anyway, cool story...thanks for sharing! It really shows how you should always keep flying the aircraft...no matter how dire the scenario is.