... Then wouldn't Boss be unaware that it's drugged because that's how he's made coffee this entire time? Seriously if Coffee has been drugged the entire time then the government would have lost this secret.
Then Sojiro is innocent. So how did caffeine fall into Shihdo's plan? I mean unless you can prove he's existed longer than caffeine or he has a time machine then it couldn't have been a part of his plot.