Call up all of their close friends and family members to notify them of your friend's drug use, then set a date and time to arrange the intervention. It is OK to exaggerate just how bad their abuse of drugs is, so spice it up a little bit. Maybe they ran over an elderly woman while driving a lawn mower across the city. Or, perhaps they lit a Babies R Us on fire during their semi-annual sale. It's all up to you. The more elaborate, the better.
Get them to come over to the intervention meeting area by tempting them with things they enjoy. This way you can assure they will show up and not have to start searching local head shops for them. For example, you could say that you are playing Call of Duty and ordering pizza and root beer. As long as you combine some sort of activity that can be played while sitting on a couch and a high calorie food, you'll be set.
Have a friend sneak into their
This is where he arrives and everyone is sitting in a circle waiting for the intervention to begin. He may act confused and question where the XBOX is and when the pizza is going to arrive. This is the time to let him know that he is here for an intervention, that you all care about him and all that bull shit. You may have to explain this several times since stoners have a hard time understanding things people say the first time. This is when you bring out his bag of bongs, pipes and other smoking devices and beat it with a aluminum bat. Then, he should understand.
Now that he knows what is going on, have everyone that came tell a story about when he was stoned and how it affected them. It could be the time he got high and fell asleep on the couch so you could hook up with his sister in his room. Or, when he was too blazed to go to the football game and gave you his tickets for free. And of course the numerous times he drove everyone home from parties because they were too intoxicated to drive. You know, gut-wrenching stories.
This step involves their side of the story, where they can attempt to explain themselves, and why marijuana is not negatively effecting their life. But, there are a few rules set in place. They cannot use the words: "bro," "totally," "uh," or "Phish." This will make it almost impossible for them to get through a sentence, and eventually they'll just give up because stoners are not very talented linguists. Unless it's about dreams, the purpose of life or outdated weaponry.
We now want to alleviate his downtrodden attitude and come up with a solution for his addiction to this menacing stimulant. It is difficult for many stoners to quit their drug cold turkey, so advise him to try other drugs in order to ween himself off of marijuana. Cocaine, PCP and black tar heroin will surely help in this effort. Have the community drug dealer present at the intervention in case he has any questions.
Redesign their apartment. Instead of multi-colored bean bag chairs, buy them actual furniture like chairs or couches. Replace their beaded door curtains with actual doors that don't poke you in the eye every time you walk through it. Those random exotic animals that he owns? Throw the snakes, geckos and parakeets out the window and buy him a cute puppy named Spike, not Blaze, Marley or Toke. Next, is his wardrobe. Discard his beanies, ponchos and hemp-made clothing. Substitute his stoner-wear with clothes that have collars and buttons. And finally, supersede his collection of horrible reggae records with books, which he could eventually learn how to read.
Do not forget that this will be a long and hard process, which will be met with resistance. He might even attempt to fight you. But, that should not be too much of a problem for you since stoners are usually too busy to go to the gym. Most stoners relapse within three months, or immediately after listening to a Pink Floyd album or seeing any Cheech and Chong film. In the end, your friend will be less annoying, lazy and dumb. And most importantly, stop eating all your fucking Cheetos.