Kaneki and Hide are tragic for so many reasons. No matter what Hide did for Kaneki, Kaneki would not have chosen him first. But at the beginning of the series, Kaneki begins isolating himself from Hide to protect him even though Hide never asked for or wanted that. Kaneki and Hide are stuck in a cycle of mutual destruction wherein the other does something reckless to their life for the other. But towards the end of the series, even after their talk, Hide knows his place in Kaneki's life. Kaneki cannot and would not choose Hide over Touka and the others because he knows Hide needs a "normal life." I think part of why they're so devastating is because they spend most of the series so concerned for the other but in the end Kaneki wouldn't choose Hide because of his own internal struggles. Hide chose Kaneki first but Kaneki couldn't choose him back
the thing about hide is that he never once expressed visible hurt abt kaneki not telling him he's a ghoul. it was never a topic of discussion between them, not even in re when it's a much safer conversation to have. he never (at least openly) feels betrayed about it, and still uses his every action to get closer to kaneki and the ghoul world despite how cut off he's been from kaneki's life. and i'm sure hide was smart enough to realize that kaneki's avoidance was always about protecting him, but it's hard to imagine that he wasn't at least a little hurt at some point that kaneki wouldn't tell him. and then a couple hundred chapters later kaneki's stumbling over his words in a sewer and hide's telling him how he's always known, while offering up his own life for his.
OK, so here’s my theory for these next few updates. Somehow either the Lodgers or Robert is going to get their hands on these notes OR Frankenstein will (perhaps for proof or out of concern for his state) hand these over to them. Either way they’re going to find out the fact that Jekyll was, at the best, experimenting on himself using dangerous alchemy and, at worse, successfully permanently mutated his psyche, created an alter ego of himself and lied about it for nearly two years.
Regardless, Frankenstein, having these notes is going to play an important part to the eventual reveal. I think Virginia Ito will have a hand in the reveal, since she’s the only other alchemist in the lodgers. She might be able to recognize some of the materials Jekyll was using and a vague idea of what he was trying to do.
It’s not stated directly but implied that no one’s seen Jekyll do anything involving alchemy since The Society started. So the idea they would learn that everything they knew about him was a lie and he is a mad scientist on-pair with the woman who created a monster with dead body parts would be crazy to see. I can’t imagine how they’d react.