First of all, my brother has a fortnite account on his nintendo switch, but with the email with which he linked, he no longer has access to it. Ie if he were to switch to PC, for example, he could not log in with his current account because he no longer has his email password. Now my question, could he somehow log in to the AC, for example, without knowing the password of the linked email? Hope you have understood what I mean, thanks in advance for answers:-)
If you do not know the email address and password, you can't log in.
He can contact support to have the email and password changed. Should take a few days at most