Do not remove that yolk!! If you do the chick will die. I say crank the humidity up and hope for the best. The more you open that bator the quicker that membrane is going to dry out. IF, and this is a BIG IF , there is no blood in the vein's near the chicks head then you can start to remove the membrane there. The second you see any blood at all, rewrap that chick and leave him. It is clear that he was not ready to hatch.
ETA: after going back and looking at the picture again, he has a way to breath, I would just leave him and see what happens. It is going to take "many" hours for that yolk to absorb, if it does.