Hi Jack
I was severely abused as a kid. I had many experiences similar to the one you describe, extreme hatred and shame toward my own body, breaking down in random public places because I couldn't understand what was wrong with me, wanting to die rather than live in this body any longer. I came to find out later in life about certain key people who knew all along what was happening, though they couldn't help me. I can tell you from personal experience that, even if you don't do anything, or if the authorities can't do anything to help this kid, just having someone, even a stranger, who saw and knew makes a big difference. Even the caring in a stranger's eyes makes an enormous difference to a kid suffering with abuse. Believe me when I tell you that you are making a difference in this kid's life, even if you never speak to him.
I also know that witnessing another human being suffering like this, especially a child, is very hard, maybe the hardest thing in life. You want to help them, but you can't. The best you can do is witness. That in itself is a big part of helping that person recover. He's got his own road to travel. You're just a landmark on that road, and believe me, he will probably never forget you.
