86 yo father can't sign in with correct email/password b/c Yahoo requires verifi

My 86 yo father got a new tablet and we're trying to set him up again but I can't log him in to Yahoo. Why? No idea.
We have the email addy & password written down. But Yahoo requires a verification, even though it was verified when it was setup. The verification email acct doesn't work so we can't retrieve the verification code. I can't fix the verification email acct because it is tied to Yahoo. We have ALL of the information for both accounts, including passwords and neither Yahoo nor Google is worth a d***.

The thing is Yahoo is okay with the sign in information and the ONLY thing that's preventing us from moving ahead is the absurd need to verify the account. If Yahoo moves ahead without verifying, I can get into Yahoo and then try to fix the mess Google has made and all will be well. But no.

And no way to contact Yahoo to fix THEIR mistake without paying them to fix their mistake!

I tried to set him up with another email account but I can't because my 86 year old father doesn't have a mobile phone. I'm pretty disgusted right now and would love to hear from Yahoo that they can bypass the verification process, at least until I can get the accounts up and running. Again, I have ALL of the information as we write it down for just this occasion...and yet it makes no difference.