I strongly advise you to not do anything about it. As long as he's not bothering you, you have nothing to worry about.
But anyway, if they are cooking drugs, they'll have a lot of security- fences, cameras, guard dogs. They will also have a lot of gas tanks if they're cooking meth.
But again, don't say anything. If your neighbor gets in trouble, his friends are going to suspect one of the neighbors made a tip. And then you've got a bunch of drug addicts trying to kill you.