RIP.
One question though, which (I apologise for in advance) may be stupid. Why would such a thing kill someone? Now, I understand he has just been (in reality) hit by a tyre at 100+mph, but his crash helmet seemed in tact and I guess there wouldn't have been much head movement due to retraints (hanns device etc).
At any rate, a perfect example of why more money, in a sport that generates so much, needs to be invested in wheel tethers (testing / design / improvement).