One may find more information on child abduction by using the websites "Amber Alert" and "Missing Kids". Both sites have information on current missing children, prevention and links to report suspicious activity.
If someone you knew died, then you can click on the building in the middle of the graveyard and claim their grave. If it's someone that was part of your family, then you can usually find their grave in your inventory or (if they died in your house) at the spot they died.
Mercutio makes a pun on the word "grave": he says when someone calls for him tomorrow "they will find me a grave man." Normally that means solemn, but in this case, Mercutio means that he will be dead and ready to be buried in a grave.