Taking away his privileges, phone, Xbox. Not allowed out, didn’t care how much he smashed things up. I’d personally take him to school and pick him up so he couldn’t go run off with his friends. I didn’t give him any spending money to buy what he wanted. Limited tv time. Do homework asap. I’d help though because he struggled with concentration. Only thing I didn’t do was leave him on his own, I was always there. I didn’t want him to be lonely and think he was alone. I felt bad doing most of that stuff. He’d shut down when I did take away his things but after a short while he opened up, gradually become a really good kid. Not saying this works for everyone, I’m not thick. But it worked this one time.