That being the case, I would really encourage you to find more ways to help his body to detox, and be sure that he doing these things daily and not waiting until he starts to feel bad/ herx. Sorry, I'm not sure how old your son is, so I'm not sure if you're in charge or he is!
A great resource for detoxing as we need to is
www.tiredoflyme.com/detox-methods.html