BINGO !!
but a good criminal interagator will get the truth out of him especially if it’s proven that he was coherant and aware of what was going on from the black box data or communications between the dispatcher and the engineer right before the accident.
It has already been reported he remembers up to the point of going into the curve. Coherence and actions performed at the time of the event is not going to be related to after the fact patchy memory that is perfectly natural with these types of concussions which often come back gradually over a period of weeks. If there was even a projectile it was minutes before the accident whereas the speed up was a minute or so before.