After I realized this wasn't a problem that was going away, I took it out of his reach. (I thought it was sufficiently hidden/inaccessible before, but the little guy is an explorer and pretty clever.) As far as the vodka goes, I definitely have that out of kids' reach. The only stuff "available" is in my airlock. I'd much rather that be in there than Star San, though. Can you imagine if he took a swig of that?
Long and short of it is that you gotta watch out for kids with this hobby.