A person that refuses to aid in the survival of all, what would you do with them?

You volunteer do help a good acquaintance sail a schooner to the South Pacific on a 5 week cruise of the islands below the equator. While way out to sea the vessel is hit by a fierce storm and took damage. She is taking on water and can’t sail under full rags. To make matters worse, the bilge pump goes out and a manual one has to be used. Everyone agrees to take a shift. When it comes to the shift of your acquaintance’s nephew, he refuses to work the pump; claims he is too wore out doing other things and repairing rigging. What would you do? Everyone else takes their shift no matter how tired. If he doesn’t want to do his part to keep the vessel afloat, how would you handle the situation?