Well you kinda missed the point..
@Happycarrottop
His son did spend money. His son also realized that Christmas is about the time and effort his father spent on raising him. He realized on the way to his dad's house that a simple material gift probably something nice, is far from what his father could really care for.
All his father wanted was a good son to be raised like his good dad. I believe that was what the flash artist was trying to convey.