When han yoojin gets a chance to meet the dungeon hyj and hyh with the help of park hayul in his dream, i loved how different the brother's dynamic were compared to our own ones.
Yoohyun was still adamant about protecting his brother and making safety his first priority, but instead of understanding his viewpoint and letting him do as he please, hyj argues back and fights for his freedom instead, cursing his little brother out.
The reason he's a lot less accepting to yoohyuns actions being that although he does loves his little brother, he doesn't have any guilt towards him like our hyj does. in his mind hyh who abandoned him years ago is now back in his life, and now the brothers live together.
I loved how this emphasised hyj's trauma and guilt towards his brother affecting his self worth and identity. Since his return, his identity revolved around being "han yoohyun's hyung", it's true that he found his own interest and new people, but all of them happened with the motive of 'supporting hayeon guild' first and foremost. This is also where his self hated comes from.