I've sent him a kind of "go back to zero" procedure.
1-pull the pedals, pull the cleats. Clean the cleats and deburr anything sticking out, inspect for broken parts.
2-Reinstall the cleats, make sure the rubber center boot is there, and all square washers.
3-Clean and lube the pedals, then "zero out" the float by running the screw midway from full R to full L. (Centered on Arcs?)
4-Run the float all the way counter-clockwise.
5-Reinstall the pedals, and see what happens.
6-If they work, they should be loose. Slowly advance the tension until you think you have them right.
My guess is that if the L one works and the R doesn't, either the pedal is bad, the cleat is bad, or his R leg originally belonged to someone else.
Anyone, feel free to add to this. I'm sure we can have him spinning circles in no time.