Q: Locked Out of Apple ID - HELP PLEASE

Hoping someone can help me get back into my dads old iPad for him.

I managed to fix it for him after he threw it on the floor with the help of google/here, but I couldn't sign into his Apple ID at the time as it didn't accept the email address he insisted was correct.

I don't live nearby, so I brought it home with me some time ago to try & fix it again, but I have only just today found a very old talk talk email address for him & Eureka!!, it accepted it with the password we both knew to be correct.

Only then it tells me that the account was suspended - takes me to a page with security questions - which he can't remember the answers to (he's 80 & unwell at the moment) He also tells me he thinks his cat destroyed a notebook I wrote all the original passwords & emulsion for his various accounts - so I'm winging it a bit

I guessed one of the answers correctly, but of course it doesn't tell me which one - a few goes later with the other & it now won't let me in again & insists on sending emails only - but that talktalk email address doesn't exist anymore

I do remember at the time of helping him set the AppleID up, I gave my own email as a back up email address for his AppleID account, so I could hopefully help if anything like this happened - but I can't see anyway of getting Apple to send to this email address, rather than the now defunct talktalk one

I'm tearing my hair out here - Can this be done ?? & if so how please

Thank you