Who the heck says that?!?!?
Another reason to NOT grip the steering wheel is that you can break your wrists and/or arms from either the impact or having the steering wheel turned suddenly as a wheel hits something. This is more prevelent in manual steering rack cars and formula cars.
Looks like the car had a hard top pre crash so he probably figured he did not need restraints. I have heard that the hard top in our car does the same thing. I watched a video of myself spinning into a gravel trap. I let go of the wheel right before I thought I was going to hit the wall (which I didn't). I was proud until I saw in the video that tried to start the car with the key!ARM RESTRAINTS!!!!!
I have always heard, and done the opposite.