I've seen this before and still see it today in players at a top level. Spend enough time training / skating and the body does adapt and they learn to balance over the skate blade. It doesn't mean the pronation / supination has gone, it's just nullified enough so they can skate. The sad part about this is that it isn't identified early enough and hence the skater never reaches their full potential. As the skater gets better they don't want to do anything that might interfere with their skating ability, even if this might mean they skate better in the long term. It's the short term view that rules, I'm on the team and I'm not going to do anything that might put this at risk. Ultra stiff, well fitted skates do help as they help to lock the ankle straight and reduce any deviation in the subtalar joint. Given the level he skated at, I'd leave it alone. You could suggest that he might want to try a small shim and see if it made any difference but I suspect it will be very hard to get him to change given his history and possible mind set. Which goes back to my earlier point, it's a shame to see these players never reach their full potential but for a someone who knew what to look for during their formative years.