Mcgrath, your point about the Piano is intersting but is answered as follows.

A piano can be played one handed and a guitar cannot.

To play one single note on a guitar, unless you play in the style of Stanley Jordan or any of his clones, you are required to strike te string with one hand and depress the string with the other.

The strong hand is the better rhythmically and that is why it is the preferred hand for striking the strings. It dominates the left so that when the left depresses the string to shorten or lengthen it, it does so with better rhythmic timing.

The other way around has the striking hand following the fretting hand, which creates big complications in terms of adaptation for the reverse guitarist. He would effectively have to train his dominant hand to be subordinate to his weaker hand - good luck!

As for the question of his already being a virtuoso, you say that explains a lot? would you mind expanding on that point?

And whilst doing so could you bear in mind stevie wonder, ray charles, Jeff Healy amongst numerous others all of whom became notble artists despite suffering bigger limitations "when first learning to play"