Reset to factory settings without AppleID password

My elderly father bought an Ipad and used it and now he somehow set it to do a factory reset. It asks for his Apple ID password and the Apple ID that is associated with the Ipad is not being used and he never really used it. He must have set it up and set up a password and never used it. He does have another Apple ID he does use, but the Ipad is not on this one.

When we try to reset the password on the Apple ID it asks for us to enter old passwords we used on this ID and we don't have any since he only used it once. So they won't validate changing the password.

How do we either change the Apple ID password OR reset to factory settings without the password? He loves his Ipad and is on a fixed income, so can't buy another one.