I tried the throttle rocker before, and it is a good thing it can be removed or pushed out of the way. Around town if you hit a bump, dip, or series of dips in the road, the palm of your hand will hit or press on the rocker causing the engine to rev or waver in its revs, possibly unexpectedly. It is just the way it is designed...it is more for a long snoozy ride on the interstate-yet even on the interstate it may have unexpected problems...hard to say, because I got rid of mine as soon as I tested it out.
I tried the vista cruise they work well(be prepared to do a little alteration with screwing or using epoxy glue to glue a tab on your plastic throttle control housing) no big deal though and there are plenty of tutorials with pictures to be found on the net for this.
Recently, I have been using a simple O-ring I found at a hardware store...if you have bar ends they work well. it allows enough friction to keep the throttle at a certain speed yet doesnt lock the throttle tight and you still have full control if needed. No alterations needed to install or uninstall and it cost less than a buck.
Also what grips does he have? I could not do 25 miles on my bike with its stock grips without hands going numb and tingly...after installing a set of PRO GRIP 714's I can do 200 miles (maybe farther I have only done 2 hundred mile trips since I installed them)
like you mentioned,the angle of the wrists when riding has a lot to do with it, the wrists need to be straight so as not to cut off any nerves or circulation...also the handlebars can have risers/pullback risers installed that take the weight of his upper body off the handlebars more...this puts his weight more on his butt than on his wrists..yet then he maybe looking into getting a better seat (think movie theater seats)
