PLEASE consider training him outside of PADI (NAUI comes to mind) if you value his safety.
Wow, ***? Although several subsequent posts mentioned this comment, I can't believe nobody has seriously called you out on this ridiculous, insulting, baseless, bash against PADI, and by extension, thousands of dedicated, hard-working, and talented instructors. I make my living teaching kids, and teenagers using the PADI system. You are implying, on second thought you actually say, that being trained under PADI system, which BTW is really not all that different from most of the other agencies, is not only inadequate training, but actually placing his child in danger!
Care to back that up with anything that does not stink of just your uninformed opinion? Your comment adds nothing to the conversation (although, in fairness neither does my reply to you), and is extremely irresponsible. You were not trained by PADI. Do you have some first-hand experience, or knowledge that leads you to think that PADI training is actually dangerous? Maybe you should start a separate thread if you feel that strongly.
The OP is a fairly experienced diver, who is quite capable of making up his own mind. He asked for information, and opinions about a 10 year old child learning to dive. He did not ask for your completely random attack on PADI, or the instructors who teach using this system.