The pranksters added so much salt to the liquor that it killed him via salt poisoning because he couldn't taste it and became too intoxicated to realize he was dying. Same reason why drinking seawater can kill you in a stranding situation.
From the web: "The Korean, Chinese, and Japanese words for diabetes are based on the same ideographs which mean “sugar urine disease”" And that's pretty much what they called it.
"I didn't know people back then knew what diabetes is" Wait till she finds out about the ancient brain surgery. Knowing about diabetes is nothing in comparison to this knowledge.
