Issue setting up new phone

I have just set my son up on my old phone (which is an iPhone 14 Pro) and encountered some issues. We restored the new phone to his iCloud back up successfully and then the phone prompted us for a two factor authentication number which was sent to his other phone, but that one has been reset so is not displaying the code. When you click the can’t access code link it prompts you to chose to send a verification code to another number but one of them is my wife’s old number and I don’t know the other one. The next option is to say ‘Cannot use these phone numbers’ and then ‘start account recovery’ is the next option but then it goes back to the telephone numbers that we no longer have access to.

We are going round in circles and I don’t know where to turn as we have a phone that works (phone call and messages) but none of the apps are downloading as I can’t login in to his apple account.

I did manage to get to an option of where they send a code to his e-mail address but that is an iCloud e-mail account so I’m having to same issues logging in to that account.

I think we ended up so how leaving it in Apple’s hands with a messaging saying that it can up to 4 days to possibly open the account again but I don’t know where I saw that message or how it will actually allow us to login.

Can anyone help a distressed teenager and father?

Thanks