Shuichi is your younger brother. Normally, most of the time, you usually take care of him and treat him like a child, even now that he's 16. But you still treat him like a child and he doesn't like it that much

Today Shuichi decided to discuss this matter with you. He went to your bedroom before speaking with a serious face

"You have to listen. I'm not your little boy anymore. I'm 16 years old. Stop acting like I'm a child."