You could:
A. Share the track with him, so that he knows what his route is meant to be
B. Use the route shaping tool to drag the route away from the road and then bring it back again. That will create a shaping point at that point. Just check in route properties that it didn’t create a waypoint. If it did, change it to a shaping point
The most likely reason your friend’s versions of your routes differ, is that he’s maybe got different preference settings. Putting in more shaping points will indeed reduce the chances of a significant alteration but it might be easier if he just turned all his preferences off or at least made them the same as yours. It also assumes that he’s not running the routes you send him through some other software or third party maps.