Resetting a secondary e-mail password?!? And why?!??!

My son's e-mail account has been acting strangely by just automatically deleting read e-mails in the Inbox after just a few days, where as in the past they'd stay there forever until manually sent to Trash.  Upon trying to log in, I get a ridiculous "We are unable to change your password because there is not an eligible verified mobile number or email on file; you will need the Primary account holder to make the change for you. Once you've reset, please add a mobile number or email address to your profile so we can better assist you with future password resets and troubleshooting.

The account site is incredibly non-intuitive, even for tech savvy folks.  I spent way too much time trying to find a way to accomplish this through my own account, which is the primary.  There used to be a page that would have all of the sub-accounts together where you could make changes, but only thing now I see is to make primary, member, or viewer on the account which is beyond useless.  How consumer UNfriendly can a company actually be?

Not very excited to wait on hold for 60 minutes then speak to a service rep who won't listen to what the problem is and go through a way too long script starting with "Did you try turning it off and back on again?", then finally getting to the actual issue 30 minutes later...