I repeat what I wrote before:
Vashti said to Achashverus that you were a horse keeper for my father and he was able to drink a thousand glasses of wine and did not become drunk but you get drunk after one glass.
I think the connection is that because you are a horse keeper you cannot afford wine so you are not used to drinking, and therefore you get drunk even after one glass, but my father is rich so he drinks a lot and even a thousand glasses will not affect him.