OK
Verizon did not "maintain" any backups for y'all
They did the transfer TO new iPhone described in latter article = Quick Start asks if you want to, and does so via Bluetooth (from phone to phone)
If your grandson backed up his iPhone, he can restore his data FROM that backup
I am curious as to HOW Verizon would be ABLE to make a backup of a phone not knowing the passcode - he would have to TELL them the passcode for them to proceed
You cannot GET the passcode - it is encrypted ON the iPhone, not known by Apple or anyone else - which is why factory reset is required
If you read BOTH articles carefully, you will learn all about the issues you face - doing stuff in the right order is all that is required to