Oh, yeah----nothing to stop the parents from moving back to their homeland---except hunger, no place to live, no clean water, sanitation, no or very few medical facilities and danger from warring factions within their own government.

You seem to think that life in all the countries of the Americas is just peaches and cream.  If you had lived in countries like El Salvador, Guatemala, and Nicaragua----you'd be trying to get into the U.S. by any means that you could.  After the 2008 banking and global economic crisis, the poor, who had little to begin with----had less.  THAT was when many families came to the U.S. with their children.  Who could blame them for not wanting to see their children die or die themselves.  The comfortable don't become refugees---only the poor.