My Husband Smoked A Small Amount Of Marijuana Two Weekends

my husband smoked a small amount of marijuana two weekends in a row ( 2 uses max of 3 hits each use) and has a hair follicle test in approximately one month. he is on the heavy side. we are wondering if it is possible for him to pass this test with lots of exercise and drinking plenty of fluids. I know that it takes about a week for it to appear in the hair. how long after consumption will it take for it to stop growing out in his hair?