Thumper - thanks for helping me process.
It's option A -- I don't want to facilitate it. The last few times I've seen him he's kept the drinking to a minimum around me -- diluting wine with juice or sharing a beer with someone. Obviously I'm still not happy that he's drinking but I'm not going to freak out.
In that case does it seem like I need to warn him that I don't want to be the one taking him to the liquor store? I realize that maybe it seems silly to focus on this but I just don't think in good conscience that I can facilitate, even if I'm willing to let it happen.