How about just not taking drugs? I'm sorry about your cousin/best friend, but he wasn't very bright to do this in the first place. Look if kids smoke some weed in high school, fine. But a being a pot head at 30 or abusing more serious drugs is just plain stupid, IMO.
I am not saying you are wrong, at all (except for the pot-head part), but drugs for the most part are victim-less crimes (in his case at least, being that he worked, supported his self, and has no kids). I am not saying he wasn't stupid, we know that and he knows that. He has a problem. I'm just saying that people who desire to stay f'ed up will find a way to do so, no matter what. Now the convenience of the more dangerous, but legal, stuff is causing a hell of a lot more problems with these sort of people than the real ones would if they were legal. This fake crap is proving to be a hell of a lot more dangerous than the drugs they mimic, and they are harder to control since it only takes the alteration of the illegal chemical, and that is a fact. The legal system will be doing nothing more than playing catch-up from here on out with the advent of all of the new synthetic garbage.