I would speculate that he was unconscious prior to impact, but at what point is uncertain. If that aircraft did in fact pitch up at 10g due to control failure, he was probably asleep almost instantly. In one of the pictures there is something visible in the front of the cockpit area, possibly his helmet, but in the side view nothing is visible...
RIP Jimmy Leeward, you died doing something you loved.
Condolences to family and friends.