I headcanon Ketch is all over 'alternative substances' ....
You know what, I think you’re right. But I don’t think his idea of a good time on drugs and DEAN’S idea of a good time on drugs is the same.
Dean is the “let’s split this joint and watch movies under some warm blankets and eat nachos” kind of dude
Ketch is the “let’s do cocaine off a stripper’s ass in the casino VIP lounge on a Tuesday afternoon” kind of dude
(Ketch is a thrill-seeking adrenaline junkie - motorcycle, tattoos, reckless awol missions/problem with authority, indiscriminate killing. Dean is not. Often they are poised as the same in canon, but their reasons for doing similar things are different, which I think would translate here as well.)