Easy- Tell the kid they're going to visit some relatives in somalia and are going to stay for 3 days and return back. So in short, you lie to them.
For the first 4 months, he's going to be really troublesome and angry that he'd been lied to but by bit by bit he will integrate into the culture.
Also don't throw him in those Somali rehab centers under any circumstances.
Most young boys are really stubborn, so there's a high chance he won't eat anything (They mostly serve cold borosh so i cant blame em), i had a friend who was sent there and he came out a stick. He'll be whipped too.
Best bet is leave him with a understanding relative.