Not sure, but I'd be surprised if he would have been on board during the actual airshow. That's generally a crew only function for safety as we now see is a smart call. The observation flights are usually before or after the days events.https://twitter.com/i/status/1591544842785796097
This video offers more questions than answers. From the angle it appears that the P63 didn't start turning till just before impact and was approaching from the rear. Sure looks like the B17 should have been visible, even out of his peripheral vision, if he was keeping an eye on the fighter lead.
Where was the airshow traffic coordinator? He should have spotted the situation and told the the P63 to abort and break high.
Last, gotta feel sorry for the kid asking if that was supposed to happen. He'll be having nightmares for awhile.
What's the point of an open door policy if inside the open door sits a closed mind?