How to request access to a deceased family member's Apple account

my dad recently passed away, and he was the organizer of our family thing in icloud. We dont have any of his passcodes since he and my mom had separated, and he was a very careful person. I genuenly dont know how we can leave and create a new family since we cant change any settings. I have tried looking up what to do but since we dont have any passwords it seems close to impossible. Im really stuck in what to do, any reccomendations are appreciated!

We dont have access to a mac.

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