Do you think he passed his drug test?

He should be okay and here is why.

Marijuana has a half-life in your system. How long it takes to leave your system depends on how much you smoke. But the time maxes out at around 45 days. One smoking session for someone with a clean system takes about 3-4 days to be clean. Smoke 2 days later and then have to wait about a week, and so on. The time it will take roughly doubles every time you smoke until it maxes at about 45 days to be clean. So if you are maxed out and you wait about 2 weeks and then smoke again, you're basically back to 45 days.

Marijuana can be detected in urine for nearly a week after smoking. Blood tests can be more accurate, and it might take a month to be totally clear. Hair tests show every drug ever taken when that hair was growing - this is why you see so many drug addicts with shaved heads or buzz cuts, by the way. Also by the way: taking laxatives and drinking wacky chemicals won't "cheat" a drug test. It will just make you go to the bathroom! These drug tests are designed by experts who anticipate what the drug user might do.

Be very careful of "remedies" for getting around drug tests. They flat out do not work and could do damage to your body.