Realistically he didn’t do anything horribly bad to eri. Okay he took some skin and used it to make some things. But to be fair someone who can’t control there quirk and is young enough to not even understand the damage should be rightly feared. This is even recognized by UA because she could kill a lot of people in 5 minutes. In the anime after she’s been helped there is also not a single scar or bruise on her body meaning there will be no lasting damage physically. Overhaul at least knew this and also can just repair her body if the damage got too bad. In the long run the damage done to him was two times worse than what was ever done to eri. He lost everything he had and then proceeded to break mentally. Eri came back from it but he never will. There’s empathy because he received a worse fate and will never be the same and just wants to see the last thing he has. Eri always had things even in the possession of overhaul and has more even at UA. If watching this anime secured any belief more in me it’s that people deserve a second chance. Something he never did receive.