Hey There. I Have A Buddy Playing College Sports And

Hey there. I have a buddy playing college sports and I was wondering what one of the best ways of cleaning THC out of your system is? He reports for move in day on August 18th and class starts around the 26th and he stopped smoking yesterday. He works out every day and has very little body fat at all. He sweats a lot and smoked daily for only about 3 weeks then stopped for 2 weeks and last night was the last time. Any advise?