I purchased for my wife as back-country boot. I am not sure how well they work with traditional resort bindings because the heel may not be wide enough.
They are suitable for downhill skiing. I just wore them last weekend. However, I have a concern if the boy has a wide foot that they might be tight. I suppose you can always order them and try them out to see. They are great boots of high quality and work wonderfully. If you are talking a Mens shoe size of 10.5 I would order a half a size larger at a 44.5. Just a suggestion. Hope everything works out for you!