ipad activation, owner is dead "my granddad"

Hi apple users

I am sure you hear silly explanations all the time but I have quite a predicament, As my granddad died last year 😢. He left me his ipad and a booklet with all his info from signing up to sites. So i thought it would be easy to log into the ipad and make it my own, but it seems that a lot of his old site data has been removed "like his yahoo mail account" as my mother closed many account when he died. I know his apple id and i have a list of his used passwords but none work. nor does his apple mail.

I would be upset to throw the ipad away, surely there must be a way to unlock it in store. I can bring his death certificate and id, and if needed my mum who took control of his assets when he passed away. would that get me any where ?

Thank you for your time and help

from edwin