iPad factory reset without Apple-ID

Take the device, the original purchase receipt with the serial number, a copy of the death certificate, a copy of the will or a document that shows you inherited it, and a photo ID to the nearest Apple Store.

Genius Bar Reservation US

or contact Apple ID Support. They will need to see the original purchase receipt/paperwork also.

Apple ID Support

Apple ID Support (2) 

Apple Support by e-mail or chat         Select your device, Battery, Power and Charging, then Power adapter not working to get a chat option. 

Apple Support using Twitter

Or fill out and submit this form.

You are welcome. You can try using the death certificate, but normally Apple requires the original purchase receipt to prove the device isn't stolen.

You are welcome.