probably he is cleaning up the sell orders right above his buy wall as well, slowly but surely. The sell wall was 13K+ at the beginning. Some people sold into it and went down to 9K. Then he replenished it to 12345DRK. Went down to 10K. And then replenished to 15K. This explaines the 8K+ DRK in his account. He has more BTC where it came from as he said.
Or he has that buy wall on Bitfinex and is unloading on Cryptsy.
That's what I'd do.
If I was in trading mode, I'd nail his entire bid on Bitfinex and dump like hell on Cryptsy too. See if he panics and buy into that.
Otoh ain't no trader-type like you and I. Dude made it big with Bitcoin for a reason.