Hi Terry,  I would say that it's a tough call to say whether the motor
is or isn't salvageable without getting to it and trying a few things:

1. Worst case situation: you wouldn't have to replace the entire motor,
but maybe he'd need to replace the slide board that was oiled.

2. Sanding the board and washing it (and drying it) with a grease
cutting agent could help.

3. A fine coat of lacquer or shellac could seal the board and solve the
problem.

4. Apply graphite.

5. Replace the felts in the guides.

Good luck!

Eli Shahar