When I was in the Air Force, they told us that they do not care if someone tried a particular drug once, but if they tried it twice they were considered addicted.
In a strange way, I can see their logic.
My point is, that the drug taker may be addicted to it. In that case, the best recovery from an addiction is to have a personal desire for recovery. That is, they must want recovery for themselves, not for other people, places, things, or situations. In this way, they cannot blame other than self if they are looking for a scapegoat, or a reason to compromise.
So, how can somebody help an addict to stop taking drugs? The best thing to do is to inform them as to where they can get help, like a rehab. Then they cannot claim ignorance. Then it is up to them to seek that help all by themselves. This usually happens when they hit a rock-bottom.
I know this sounds tough, but it is tough-love that seems to work the best.