I think JBR thinks the memories belong to YH because he believes he is a good person,I mean he even doesn't have the whole truth about himself ;there are still many holes in his memory,so in my opinion at the end he will discover his true identity of being a killer ,there is no brain transplant,it would be ridiculous,may be HSJ performed the surgery to save BR's life because he is his biological son,remember how precious he is considering his offspring. HSJ needed constantly mice in order not to lose his performance in neurosurgery,it's normal after all,he is a surgeon.
Sung Jieun in episode 7 was interesting. I'm wondering why she would mourn Yohan's death if she was so terrified…
I think she adopted YH and didn't tell him the truth about his identity,so for a long time he thought he was HH's son,for sure he is not a killer,his eyes are full of emotions; he lived a life that wasn't his,it was really unjust,so yes he is a poor guy
https://www.twitch.tv/iro43oeifnbjg
https://twitter.com/wdldlsdn/status/1351381509123424258/photo/1