It is claimed he received what is called the head injury protocol ie he was given a prolonged general anaesthetic or what the media called an induced coma. There is very little reason for this other than a head injury.
Any 'induced coma' will produce profound retrograde amnesia. The head injury may cause long term memory loss and amnesia. Now add in PTSD
ANY comments or statements he has made since the accident are IMHO worthless. Even if he cannot recall the minimum speed for rolling out at the apex this does not mean he did not know it at the time.