Greg still needs to surround himself with higher caliber people. Chance he didn't know she was doing hard drugs = 0%.
Find a new gal Greg.
And we're sure he's not? I mean, drug tests are essentially marijuana tests. Coke is out of your system within about 48-72 hours. Unless you're a total cokehead or have poo for luck, you're probably not gonna pop a positive for coke on a random.