He is not your biological younger brother, he is your adopted younger sibling because he was adopted at an orphanage. He was initially happy because he had a new family but he felt disappointed. his adoptive parents were strict and serious.

When he finished his mansion training and his head was bleeding even though it was bandaged he looked sleep deprived and patted his cheek and wiped his tears with fake enthusiasm.

El: "Come on, cheer up El! I can definitely do it...!"