[AaronBrown]

I find it puzzling. The people I know who did well at blackjack were obsessive card player types with excellent memories and computation skills. Several won world or national championships at games like bridge, backgammon and chess. They practiced intensely and had careful theory behind them.

That does not sound like your friend. I wonder if his edge didn't spring from a more intuitive source. He was careful enough to learn the correct strategy and he could count cards, but he didn't like to do count consistently and he doesn't seem to be working from an explicit theory.

Perhaps he has an excellent card memory that helps him predict cards without being conscious of it. If you see some cards that you saw together before the last shuffle, and you can remember the card you saw next, you can predict its location pretty well most of the time.

You'd only have to notice a few patterns once in a while to make a big difference. And your friend wouldn't look like my friends, who had to work hard to look like anything but nerds trying to count and shuffle track. He would look like a real gambler, which would be a big advantage.