Globe And Mail: DC Nixes Superman Logo Use On Memorial Statue For Murdered Toronto Child
You should go read this at their site rather than my rewriting their work. I also assume this story a) has a little more to it, b) isn't all the way concluded. At least I hope that both things are true.
I'm trying to formulate a viewpoint where allowing one family/group to do this would lead to a flood of similar uses or have another unfortunate outcome, but I have a heart of stone and it's hard for me to manage that mindset for more than two seconds. It also strikes me that this is a reference rather than a use, so I'm not sure why DC would have anything to say about it at all. Then again, I don't know the law.