See if she can recover the ID/password.
Apple ID - How to find your Apple An iCloud e-mail address is an Apple ID.
Enter the Apple (iCloud) ID and click Forgot Password.
If she can't recover the ID and password to log out of iCloud or go to iCloud.com/Find My Phone and erase the device, then remove it from her account, the device is useless. Return it for a refund.