What should a motorboat operator do when someone is being pulled into the boat of the water?

Shift into neutral, be aware of where the rudder and propeller are relative to the person coming aboard. Keep the stern of the boat away from the person in the water. If its a smaller boat be aware of the balance issues. If everyone goes to help the person aboard there may be more people in the water. It might be useful to approach the person with an eye to the wind or current to make the boarding operation easier and safer. Ex approach upwind and drift down to the person.

If there are possible injuries involved be aware of the need not to further injure the person. Someone may have to enter the water to assist them wearing their personal flotation gear. There are several techniques for boarding boats with higher freeboard.