PharmaPhreak- I can offer some advice in this area.
I had to take a drug screen 2 different times for jobs. Prior to the jobs I had been smoking continuously for up to 6 months. In each case I quit for 21 days and took "readyclean" a detox drink before the piss.
You say your brother smoked weed 2 weeks ago, but that was the first time in a year. That is good in itself, because if you are a continuous pot smoker it builds up higher and higher in your body. The amount of fat you carry on your body is also a factor. The more body fat, the longer it will take for the weed to leave your system. The speed of metabolism is also a factor.
Anyway- IMO your bother should start doing cardio for at least an hour a day to try and increase metabolism and be drinking at least 2 gallons of water a day, more if possible.
I think he may already be clean but I know when a job is on the line, you want to be damn sure. So, have him do these things mentioned above and also have him look into some kind of "detox" drink(some say these don't help much, but I have used them twice and it gives me peace of mind).
If he wants to get creative have him find a clean friend to piss in a vial right before the drug test, then duct tape it to his inner thiegh (to keep it warm). People have used this that I know.....
Oh yeah, lol- they have fake cock system thing you can buy- it has hoses running from a bag of clean piss hidden on the body to the fake dick...this is for the people who are watched when they piss.
Hope that helped....oh yeah, check out
http://www.hightimes.com if you wanna read some more on it.