How to access a deceased one's iCloud account when iPhone is inaccessible?

I’ve tried to reset it. It keeps trying to send the code to his phone number which is now disconnected. The phone is ruined then it prompt to send a message back to the email. The iCloud email which clearly I can’t get into. I tried to update my phone number is saying I have to wait four days please. What can I do

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Original Title: i meed help my som passed away in a car wreak his phone got ruined they said it cant be fixed i finally just figure out his icloud address bit i dont know the passwoe im desperate to get into it so i can see if anything important is in there