My grandfather left home at 8 years old, and never returned, to live on his own because he didn’t want to live by the house rules anymore. It happens, because some kids are just that strong willed that they cannot be deterred.
Not to criticize the father, if the child did leave on his own like that. However, if you have a strong willed child and they want to do something, you are better off teaching them yourself to help them achieve their objective in a safe and controlled manner.
When I was 13, my parents sent me off to summer camp for a week. When I got home, I found they had moved and left no forwarding address.