I already mentioned the “Black Arpad” a while ago – a hideous chess figure which we simply place in front of the player who is paralyzed. Usually this is regarded as suitable threat to move on. But thinking about it seriously I think the best way to get players going is acting like a teacher who tries to get the right answer from his class. A teacher would start giving hints, so what players should do is to publicly and calmly talk about the options available to the paralyzed player. This might give the player a new perspective on things, on the other hand you might even make him do what YOU want instead of what is best for him, but that is left to your own Machiavellian inclination I think. But never try to put pressure on such players, otherwise they will simply shut down and play even slower.