The only test that shows THC usage after a 4 week cycle is a hair folicle test. But, a hair folicle test can cost upwards
of $75. Which, is very rare for any type
of municipal or regulated testing. I wish u luck in your trials with your nephew. I am raising my neice. I am a strict *******. But, she loves me for it. God bless. Oh, one other thing. Simply ask him if he has to pee when he is testing. If the answer is yes, then you have your answer.