Why does he live with his grandma and grandpa?

Of course my child asked me why he could not live with his grandparents too after hearing of a friend who no longer lived with his parents.  I took the time to explain how much I loved them.  I also shared that sometimes mommies and daddies love their children but do things that would not be good for their children.  I shared that in these cases sometimes the children have to live with their grandparents instead of their parents.