I hate to break it to you but even in real life, people who lost their memories are also affecting their "way of thinking".
And several cases even lowering their IQ.
Real life cases doesn't mean it's a scientific fact. Losing your memory DOES NOT affect someone's intelligence, awareness and sense of judgement.
Stop giving people excuses to lack critical thinking
IN FACT THERE ARE JOURNALS AND RESEARCH REPORTS ABOUT THAT.
Remember that Jaehee is on a BIKE ACCIDENT AND SUFFERED BRAIN DAMAGE resulting to his memory loss.
Some cases might make their IQ drops but it could get better—and it is true that most brain damage can lower his intelligence (by which I mean, it impacts his cognitive functioning, problem-solving skills, etc.)
I admit, it can affect the "way his brain works" but still, no excuse of not using it because mc can still improve his brain function/s as you also mentioned ("IQ drops but it could get better"). My original comment still stand.
You sound so ableist :/
I'm saying this because my deceased bestfriend was suffered from brain injury years ago. Some of my friend in class at first making fun of her when her memory started to detoriate. Just like you, they also thought she becomes "dumber".
It's not alwaya the case, but it DOES happen.
If you don't believe me, you can go around asking a neurology.
And how could you say "no excuse" to mc when he's suffered not only from his brain damage and memory loss, but also mental damage???
He's traumatized that his iq drops and his older brother trapped him in the hospital.
did YOU hit your head somewhere?
I honestly dislike the mc like losing your memory does not mean losing your braincells my dude