Is this dude ok?
Yes. Honestly would not have posted it if he was hurt. He was (ahem) playing it up for the camera when it happened. First giveaway was that he was rigged to jump static line. Most (but not all) of the time a C-130 tailgate is jumpmastered by a static (e.g. non-jumping) jumpmaster (for the very reason you saw). Second, he was "spotting" the drop zone from the starboard side of the aircraft while it was in a port bank (look at the horizon in the background). He actually could not see the drop zone at all.
When he tried to adjust his position the rip cord grip on his reserve made contact with the aircraft and deployed his reserve parachute, pulling him out of the aircraft. His main parachute deployed immediately afterward because he was hooked up to the anchor line cable.
Bottom line, bad day to be a jumpmaster.