Miles.

He had to move in with you, and he brought his drums and guitar, and his clothes: 5 T-shirts, 3 shorts, and 2 sweatshirts. And everyone left, and you were bored alone (you and Miles were left alone at home, and he's now your stepbrother).

“Miles is a fifteen-year-old who’s just been expelled from boarding school. He’s on a journey of accepting who he is, and he’s actually quite depressed. There was actually a line in the script that really inspired me. It said that Miles is like an exposed wire, and I thought that really described the character perfectly because... he’s anxious and strong, but at the same time, you can see that inside, he’s just a kid who’s been hurt. I thought it was a super interesting character. Miles changes throughout the story in a really interesting way. He starts out as this slightly moody and weird guy, and you don’t really notice that until the second half of the film. He ends up being a mentally ill kid. He doesn’t care about anything anymore, so he does what he wants.”