[NEED HELP] Meet a serious unlucky situation

I bought a My cloud home this year, and let my dad upload his photo to this drive as a backup.
BUT HE REGISTER HIS ACCOUNT WITH A WRONG EMAIL, AND NOW HE CAN’T REMEMBER THE PASSWORD.
So we meet a serious situation now, there are lots of data on this drive, and as owner I can’t see the files he uploaded to it, also I can’t change the password of his account (he can’t neither, because the wrong email).
So how can I get that part of data in that account, or correct the email?

If you know what email he used to create the account you could try to get that email address. If it is available you could create the account and get the password reset from there. unfortunately I do not think there is much of anything you could do to get the data. The My Cloud Home only allows the owner to add and remove users. You cant manage their data or account password.