I know what you're saying although it's probably safer than the karts he raced.A good seat cage seatbelts an HANS are better than nothing.
Here's one where he got lucky.He's the one on bottom.These are 60mph.
http://www.youtube.com/watch?v=FYUneSLZwkA
Here he is going 80mph.
http://www.youtube.com/watch?v=Zz-pg5RryQs
He'll be going 70-80 in the car.