Update after camera was found:

First the cause of the incident is a bridle under the arm when the PC is released
Second the helmet was not attached or properly attached as the chin-lock was open when found and the jumper lost is helmet before opening, which gives an outside view of the incident.

He exited and had a non effcient track but nothing very unstable.
At some point (36th second of the video) he's changing his position (box) to pitch and he losts his helmet while getting the PC out. He tries to recover it by putting his hand on his head but the helmet is already gone, we can see that he already grabed the PC by the handle.
The helmet turns and shows the all bridle out and the all the PC in the wind still grabed by the handle.
The camera losts sight and get it back (still 36th second of the video)and the PC is now in the front of the arm and the bridle, a moment later he left the PC go.
My guess is that he probably kept the PC in the hand because he was thinking of his helmet, and the air perturbations had made the PC turning around the arm followed by the bridle.
The camera losts sight again and when it got back on him for 2 frames (37th second of the video) the right arm looks like he is trying to do something but we cannot see the PC inflated.
The camera losts sight again, it got back on him (38th second of the video) and something that looks like the inflated PC but he his already far from the camera.
The next 2 times (39th and 40th seconds of the video) we can see him it is very hard to see what's happening but I would guess that he is trying to do something.
And then (41st second of the video) he is on the ground.

Lessons to be learnt:
Never keep the bridle in your hand, if you go for pitching do it fully whatever is happening.
Check your gear, 1, 2, 3, ... how many times needed (whatever people are saying).
Think about what you would do if you were in the same situation now, and train it mentally and on the ground, so the day you need it you will do it fast.