You can get your mother's permission to create an account on her behalf and show her DNA information. Once she gives you permission for both of those, you just need a different email address. Edit your mom's profile to put in the email address you wish to use for her account. You can then log out of your account and create a new account for her using the invitation email sent after you edited her profile to add the email address. Once her account created, you can log in as her to enter her DNA information. Other than getting her profile public and adding her DNA information, there is no further need to be logged into her account and you can log out and return to your account login. Just retain the password in case you ever wish to edit or add more DNA information.