What is the quickest way to learn the letters labeling the chess moves? What do each of the letters represent?

I would say just play a game, and after every move, click the "Moves" tab, and see what it labelled it as.  As far as letters, you have:

K-King, Q-Queen, R-Rook, B-Bishop, N-Knight, P-Pawn, O-O Kingisde castle, O-O-O Queenside castle

Once you play a lot, you'll find visualizing the chess board a lot easier. Blindfold chess is fun too.

Simultaneous blindfold blitz is fun too. It may be a week or two before he's ready for that though.

I would be amazed if someone who's having trouble with algebraic notation in their mind's eye can play simultaneous blindfold blitz in less than two weeks.

 Yes, or blindfold chess.

I've played chess off and on for years, and there's no way I could play chess blindfolded.

Some strong players, like Class A USCF, proclaim they can't play blindfold. At the same time there are much weaker players who can pull it off.

As much as anything else, it's probably a matter of desire. If you practice you have a good chance of managing a game blindfold, given some minimum level of chess ability.