The best thing you can do is several things.
Get him into a good Church where there are kids his age. Ask if the Church has a Youth Group leader. Bigger Churches usually do. And take him! It might take a few weeks 6-8 till he feels comfortable.
Get Him into Sports! Playing Football or Basebally or Soccor or Basketball at the school or in a City Program will do wonders for his self esteeem. HE NEEDS THIS! MOST BOYS DO! Sports changed my sons life!!
Take him to MHMR and see if he has any issues, He could be Bi Polar, or Depressed, or have ADHD! Call your city Health office, its very cheap and almost free.
Get into counseling if you can. If he came from a "HARD PLACE" he may have pent up anger, fear, saddness, low feelings of self worth etc.
Try to take him places where he can be a kid.
Camping is great, Boy Scouts is even better. Where the pressure of being "COOL" is gone. Schools are brreding grounds now for bad behavior, Gangs, etc...
He needs to feel a part of something and getting into trouble might mean hes trying to be COOL with the BAD KIDS.
Church, Sports, Dr. and Counseling.
Also, Get a big Chalk board or Dry Erase board and write up the house Rules.
Such as Lay out your clothes the night before.
Make your Bed when you get up.
Brush your teeth,
Put your dirty clothes in the hamper.
help set the table.
Do homework when you come home from school.
No Video games till 8-9 pm.
Say Yes Ma'am and yes sir
Keep your hands to yourself.
Help mow the grass on weekends, etc.
No backtalking.
No swearing or bad language.
No friends over unless you ask first. etc.
Give him an allowance of $12 a week for a $12 year old if he follows the rules if he breaks them. he gets nothing.
Give him extra $ to wash the car, or to help you with bigger chores.
Folding laundry etc.
Think of what the MIlitary does to young men and women when they go in.
They have rules, they have to Earn rewards, and they learn to take pride in their appearnce keep their rooms clean etc..
Of course give him lots of hugs and love too.
He nees God, Sports, Friends, Rules and Boundaires and Love.
I wish you well! Keep us posted