Just fixed my phone and then it disappears overnight, is there a way to override the ring volume to help in the search?
If you still have your grandson's gmail account for the lost phone and haven't replaced or found it you can download Plan b to it through the google play store or android market on your computer by using his gmail account. this only works if his phone is android. I don't know the equivalent for apple phones. if the app does not launch properly then all i can say is try talking to Verizon about replacing or even tracking the phone through it's number or his plan.
Good Luck. Hope you can understand what i'm trying to say, if not then just post questions at this thread and i'll try to provide better instructions.