Not an answer, but a strategy to get one: I would start by googling 'alcohol-resistant caulk' or 'alcohol-resistant sealant'. This will give you hits for chemical companies that produce such products. For instance,
claims to have an epoxy ("UV18MED") that is alcohol-resistant and can be used as a sealant.
claims to have caulks that are resistant to alcohol.
Since each of these companies are experts on the properties and performance of their respective products, you should call them, describe your specific application, and ask if they have anything that would work reliably. That's the best way to be assured the product will do what you want.
One problem you might run into is that these may be B2B companies, i.e., ones that sell in quantities designed for businesses rather than consumers. If that's a problem, try calling some manufacturers of consumer adhesives and asking if they have anything.
I know this is more work than simply posting a question on CSE (and there is of course nothing wrong with posting such a question), but it's only by speaking directly to the manufacturer that you can be sure the product is designed to work in your application (unless you have a product label that indicates this).
While you're speaking to them, you might also want to ask about leaching -- whether components of their product might dissolve into the alcohol; you would need to judge for yourself how much leaching your system could tolerate. You'll also need to let them know what kind of mechanical stresses and temperature changes the product must tolerate (e.g., an adhesive that is sealing an aquarium and also holding it together needs to be a lot stronger than a caulk that is merely sealing the top of a sink). The more specific details you can give them about your system, the better.