In Costa Mesa, California, father and son, Chris and 18-month-old Cooper O’Brien, share the same routine every morning — sitting on their curb to watch the cars go by. Now, their "Coop on a Stoop" videos are enjoyed by millions. David Muir reports on World news Tonight's Person of the Week, and the family's hope that the simple joys can unite us. https://abcnews.link/TYipqno | ABC World News Tonight with David Muir