Read more: Marijuana Detox
Animalcracker, instead of just lol'ing at you, I'm going to give advice, so please listen. Despite what you may read or hear or watch, you do not have to detox from marijuana. Nor do you have physical withdrawals. Cannabis is not physically addictive. It sounds as if your nephew is having withdrawals from a REAL drug and is not being honest with you. And instead of "shipping" him back, you might actually be able to save his life. Often times detox'ing requires medical attention (due to dehydration etc) Dont ship him back because all he will do is go back to using.
You need him to be honest with you and let you know what he is coming off of. And he needs to do it NOW.