Get her to to check the connection where the cable from the morse control joins the lever on the gear box.
The lock nut on mine came loose a while ago, which allowed you to increase the engine RPM but not alter the direction of travel of the boat.
Luckily was an easy fix, just had to adjust the the nut position on the threaded part of the cable and then do up the lock nut.
I hope this makes sense, it's easier to do, than it is to write down.