Old email address to new account

I’ve had an email address attached to my account. It’s forwarded to my gmail account. I noticed that it quit working. A year or so ago, we transferred all the cox account to his name. Is there anyway to transfer that old email into his account? I’m not able to open a new email bc they no longer offer it but all my password recovery emails are going to the Cox.net accounts and I’d like to access them to change the email address, even if temporarily. Or i would like to ensure that the email address is not being used by someone else now. Yikes. I am not sure when the old email quit active as I wasn’t notified.