Cannot access my blueyonder email via my virgin media

I am the account holder of the main Virgin Account.  Up until recently wer were all able to access our blueyonder email. I, the account holder can still access mine and so can ons of my sons. My other son has recently been unable to access his blueyonder emails. He changed his password and then reached a screen suggesting he link his email to Virgin Media 02 ID. When he tried to do this it confirmed that the account is linked to my gmail account. On this screen it says that if my son would like to continue and link his virgin media account to his Virgin Media O2 ID he needed to confirm the full email address the Virgin Media account is currently registered to, which is me, in order to approve the transfer.

Can you tell me whether this is the correct way  that will restore his access to his blueyonder email.