Is he seeing activation lock?
Briefly, under these circumstances, to remove the activation lock he will need to have the Apple ID password used by the person possessing the device prior to its erasure (or be able to answer the relate security questions), and we can't help you with that. And, Apple support will not help unless there is an extenuating circumstance (e.g., you have the receipt for your purchase of the device with its serial number on it or a court order instructing Apple to assist in the provision of access to a decedent’s information from the deceased person's accounts). To deal with the possibility he has an extenuating
circumstance, use these support options:
Get a call from Apple support to help solve your problem using this link https://getsupport.apple.com/?caller=kbase&PGF=PGF63005&category_id=SC0245&symptom_id=23362
Apple ID Support https://support.apple.com/apple-id
Apple ID account security for country-specific and region-specific help https://support.apple.com/en-us/HT204169
Get Support: We’re here to help https://getsupport.apple.com/. Go through
the options to find the best support option.