Next to pitching, catching still is and probably always will be the fastest way to a college/pro offer unless you are a 5 tool SS.
As far as what you can do to help...
Footwork, arm action, and the mental side are the 3 most important, but they are only important if the kid has the "HEART" to play that position. It isn't an easy position to master and it gets harder and harder to love with every level you go up unless you are passionate about it. You almost have to love taking the beating and not getting any praise for it.
Purchasing a good jump rope and becoming its best friend "daily" is a huge start. It is one of the best exercises to improve a catcher's footwork and get his body in complete shape.
Getting on a good throwing program designed to shorten the "load" pattern when he throws is crucial to shaving tenths off of a pop time. Although the throwing motion itself is no different than another position, the load is much more compact. This takes tons of repititions to master.
Like Dallas Spikes said, getting with a quality "Catching Coach" will aide in the mental side of things. He can teach you the finer things of how to read hitters, how to set up hitters, how to get in a pitcher's head to work for you, etc.
This is one of the hardest things to find in an instructor...someone that can break down the "intangibles" of the position.
Of course, we haven't even mentioned blocking, directing every aspect of the defense on the field, popups, recovering wild pitches, backing up 1st base, etc.
I wish there were more catching threads. I love talking catching and could do it all night! haha
Good luck with it.