It's interesting to think—if he could dig up that evidence now, it's entirely possible to think he could have figured out out post-facto in the original timeline. I wonder how they would have felt about that then?
Probably just that the mad empress also had a drug problem, I guess. It's only because everyone here is grappling for answers as to her sudden changes that the drugs might be blamed for everything.
(For the real and original empress, it sort of feels like it might have been depression fueling her addiction and hedonism)