The best way for your son to get involved in airsoft is for YOU to get involved in airsoft.
You get your son to engage in a healthy, fun activity and spend time with him as a bonus. It'll be four years before he is able to play on most fields without parental supervision.
So if you come out and get to know the local community, you'll likely wind up finding places to play that can involve your son as long as you're present.
Age Verifier - Lower Vancouver Island
Brotherhood of Nod - Nod Prime || Vancouver Island Airsoft League - President