It is apparently possible to have a board malfunction that damages the panel, but that is usually accompanied by a loud "pop", not just a click off as your son described.
Usually when the panel cracks, the picture disappears immediately, and if the TV is left on, boards get destroyed afterwards. Strange that your son doesn't tell you until the following morning, instead of 10PM when it happened. Did you discover the non-functioning TV, before your son told you?
That which may be known of God is evident within man, for God has shown it to them, so that they are without excuse. (Romans 1:19-20)