Can you lower the alcohol concentration of a drink using vegetable oils?
Liquid-liquid extraction is a widely used method, but it's normally used the other way round: You add e.g. ether to a solution of your valueable substance X in water, separate the phases, and evaporate the ether to get pure X. Add some more ether to the aqueous phase, etc, two-three times.

Now you can be quite sure that you have recovered all of your substance X, but also your aqueous phase will be saturated with ether. No problem if you'd discard it anyway, not so good for drinking. :-/

It's also bad if X, like ethanol, is well soluble in both phases. For hard liquor, the whole mixture is likely totally miscible, and for beer, you'll need a lot of oil to get any significant effect. And then what do you do with the ethanolic oil afterwards?