Children steal for all sorts of reasons. I stole sixpence from my mother when she had confiscated the packet of silver cake decorating balls I was playing with and dropping on the floor, to buy myself a new packet. I had a son steal from me in his early teenage years, his school friends had a lot more money than he did and he wanted to keep up. I found £5 had disappeared from my purse and told the children there would be no TV or any treats from any of them until it was returned, and that if it wasn't back in 24 hours I would go to the police. I would have done too, in those days the police were more prepared to help out with wayward children. With about an hour to go, it reappeared in my purse.
Later when my father was nearing the end of his life, my son admitted he had stolen from Grandad too, and wanted to confess. Grandad always thought the world of him, and I thought it wrong to for my son to upset him in his last few days, and told him to keep quiet about it, he would have to live with it. After a breakdown, he is now a son I am extremely proud of, they do grow up!