NY is a pure comparative fault state. Even so, I think that it would be very difficult to claim that Ward wasn't 90% or more at fault for what happened. Let me put it this way - good luck finding a good attorney to take that case on a pure contingency basis.
Better lawsuit is against NASCAR for indirectly encouraging this sort of behavior and because they'll want to settle AQAP. I know that sounds like it's removing the blame from Ward for doing something so stupid, but it's no different than, for example, a fair company allowing sliding down a steep hill as an attraction and then having someone break his neck while sliding, or a baseball park that doesn't have a rule against hanging over the railing, and someone falls.
NASCAR is substantially responsible for what happened.
Ball don't lie.