tell him to get a new job.
If his employer doesn't want people who do coke, then your friend shouldn't work there. ..."no... but I'm different, I can have a heroin addiction and still function fine."... Need to realize, there are a million reasons an employer may not want to employ a drug user... none of them are of concern to you, all that matters is whether you do or don't use drugs. I am not prejudice either way, and would have no problem hiring good people who recreationally used drugs. I also, however, support private business owners' right to choose who they hire 100%. 80% of jobs do NOT drug test... is it that big of a deal to your friend to work for a company that does?