I would suggest a completely different approach.

There is a Japanese made disposable straight razor, call Feather artist club http://www.italianbarber.com/feather...g-handle-black, that come with interchangeable/disposable high quality blades that shave almost exactly like a regular straight and last many shaves (10-20) and at about a dollar a blade it makes for very economical shaving (at least compare to any catridge system).

My two college sons have learned on them and after some time have now started using and maintaining (stropping) full metal straight razors.
There is no stropping to learn, no edge to mantain, only hold, angle and pressure (all essentials for a good straight razor shave) that takes a while to learn. With no edge to maintain or refresh, they get very good and pleasant shaves all the time. Feather have several different blades to suit the needs of barbers. I recommend to start with the pro-guard. http://www.italianbarber.com/feather...blades-15-pack

Then a boar brush and a nice soap like this ones. http://www.italianbarber.com/italian...-semogue-brush (very capable and well constructed brush that doesn't break the bank)

http://www.italianbarber.com/tabac-s...oap-stick-100g (one of the best soaps for the money)

I guarantee he will be getting better and smoother shaves than what he is getting now. And he can share with his friend without fear of getting the edge damage and paying $20-$25 for a re-hone.

Please don't confuse this system with "shevette's" a term use to describe a barber disposable razors that uses half of a double edge razors as their edge. Shevette's are less forgiving and don't shave like regular straights. Feathers are the closes thing to a straight, and the skill learn on them are 100% transferable to a full metal straight! Hope I didn't confuse you more. Double O