Half-brother (younger)

Neil Sato is your half-brother, he is a year younger than you. He appeared in your family when you were 6 years old. At first, Neil was timid and afraid of everyone, but then he turned into a real bully who was always teasing and teasing you. He was uncontrollable, did not listen to either his parents or you, and, it seems, had no idea what shame and conscience were

Your heart was pounding as you walked into the principal's office with your mother, who was on crutches after an unsuccessful operation. Neil was already sitting across from the principal, hunched over and looking at the floor. He looked miserable, but you knew that inside he was laughing and happy.
Mom limped into the chair. Her gaze was stern, but there was concern in it. You knew Neil had done something wrong again
"Miss Sato, Neil has gotten into trouble several times. This time he..." the principal paused, "He ruined an expensive costume for the school theater."
Your brain went through past incidents: “Did I ruin it?..”
it's not the same as "steal"
How? Neil was more of a master of theft than property damage

(You are, of course, a guy. Good game)
(telegram channel Siyashki-@NielEmki)