Sounds like your mate is on the road to nowhere! If one of my close mates told me this shit i would tell him to keep the fuck out of my face for being weak and even contemplating dabbling with that shit, i would then proceed to kick seven colours of shite out of the thieving bastard (because that's what he'll become) which would hopefully result in him being hospitalised for several weeks which in turn would prevent him from dabbling any further with this evil shit.Whilst in Hospital he could seriously consider his actions. Then make it your business to attend the hospital everyday and batter his head about how much of an R soul he's been for messing with it in the first place.

P.S If he keeps it up lock your doors and windows and hide anything valuable because it will only be a matter of time before he starts thieving and mugging old people to feed his habit.

Hope this helps.