My Friend Had Quit Using Methamphetamines For Quite Some Time,

My friend had quit using methamphetamines for quite some time, and seeing as it was his birthday recently we all took it easy and let him have a day. His ex got suspicious when he didn't go home until the next day, and is going to drug test him. He NEEDS to be clean tonight or he'll lose his son. Though I don't agree with the drug, I really don't agree with him losing his son over a birthday bash. Help?