Not saying y'all are barking up the wrong tree per se but I dont think theres much to the drug angle
-theres only ever the single reference to either of them doing drugs. Snorting ritalin off a hitler knife. That seems designed to shock or impress, to me. its no about the drugs per se. just like the knife isnt really about the knife.
-said in various media they didnt have any drug problems. Obvs that could be from parents or people who wouldnt necessarily know, but nothing seems to indicate they were regularly using anything, or have anytime recently. Besides perhaps BS asking about the "dry" sign at a truck stop.
-Im not from canada, but I am from northern USA in a place seems similar to port alberni, aging industry, economically depressed, rural areas nearby etc. Anyway in alot of places like that teens will experiment with drugs, perhaps especially prescriptions, and its really no big deal. people dont think of them having drug issues, they dont think of themselves as having them, and alot of times they dont go on to regularly abuse drugs.
thats a lil less common in the middle class, but in both poorer or richer strata its normalized and nbd really, and it seems like neither BS or KM were 'middle class' even if from different sides. (could be wrong about BS but seemed working class family, and as discussed KM certainly comes from money)