Can a 16 year old be handcuffed and transported home?

My girlfriend’s 16 year old son with Asperger was out walking. He opened a mailbox to an abandoned house and someone called the cops. They found him still walking and instead of calling her immediately they put him in handcuffs and transported him home in cuffs with no seatbelt on. Three squad cars showed up in front of my house and took this poor kid out of the car in handcuffs with all the neighbors watching. Now he can't sit still, he is pacing all over the place and messed up.