I’m so sorry to hear about your brother passing.
You must mean the iOS activation lock which is something that Apple added in iOS 7 to help reduce theft of iOS devices where each iOS device is associated with an Apple ID account, and even when reformatting the device, you still must know the owner’s email and password for their Apple ID in order to setup and use the device. The AppleCare article below explains more about the activation lock and your options:
It’s not going to be possible to use iExplorer to get around this activation lock. I would recommend contacting Apple if you need further assistance with it: