Hmm. I must say I disagree with extensive weight training until the body is fully developed. That said. Quite incredible what can be achieved so young.
Kids should be kids and do kid things. Without doing any research on this. I wonder how much of this is the Dad trying to relive his own childhood goals through the child and driving the child into this lifestyle.
Personally I just can't make my mind up on this, part of me thinks that it's going to create long term problems but then, there's the appearance that he seems to enjoy the training -we don't normally question the displays put on by the Shaolin troupe that often contains young children (although I don't know for sure how hold they are when they start -probably older than two though!).