Aser, that is when we would use a Hi-Line, dropped to the boat and attached to the winch hook so the boat's crew can pull the winchman into the vessel's cockpit while we maintain a hover just back and left from the overhead.
Trying to get into a boat from the water in a rough sea is very difficult, even for a fit diver, especially if there is no ladder and the boat has a high freeboard.
The Royal Navy do free drops with the diver.