The aircraft was very badly over controlled during the pre-impact, failed attempts at landing. Very surprising, if he had as much experience as reports have said (25,000 hours is a very high number for a helicopter pilot).
It made me wonder if the pilot was not securely strapped in from the beginning and perhaps got thrown forwards away from his seat. I've flown with a couple of pilots in the past who have only secured their lap belt, not the shoulder straps, not something I'd ever do.
It seems to me that a lot of torque was going through those rotors for it to remain spinning so rapidly for so long. If the pilot was "doubled up" in his seat and then pinned forward by rotational forces, he would have been unable to reach the controls properly.
Obviously, all is speculation at this stage and doubt the accident investigation will discover evidence, one way or the other.
A tragedy, whatever the cause.