Basically with a blood test, your friend is fuked. If it was a urine test, he would be okay with the opiates, but depending on how much weed he smoked, he would prob fail for that. I have smoked like 1 bowl's worth of weed 1 day b4 a Probation drug test a few times, drank a lot of juice/water and passed. However, with blood test's, the half life of all the drugs are visible for a much longer period of time. As far as I know, there aren't any method's to clean your system for a blood test...