Hair follicle drug test on my children's father?

I have a custody case coming up. I asked my lawyer to have a (hair strand) drug test done on my children's father. I think his lawyer has let him know what is going to happen, and he has quit smoking and using other drugs. It has been a couple of months or so. Will the courts be able to date back long enough to show that he was a user? If he has quit using for the time being, will the test still show he was a user? How far does state and government testing go back? Are there limitations on how a far they go back? I know employers go back 90 days, but what about family court? Anyone out there who really knows?