If your iOS device is activation locked, see
Turn off Activation Lock https://support.apple.com/en-us/HT201441 “If you erase your device without signing out of iCloud first, it might still be protected by Activation Lock. Whether you erased your own device or … [got an erased] one from someone else, you can only turn off Activation Lock by entering the correct Apple ID and password.” The correct Apple ID and password is the combination allowed by the rightful owner of the device.
So, if she forgot the correct Apple ID and Apple ID password , then use: If you forgot your Apple ID https://support.apple.com/en-us/HT201354 and If you forgot your Apple ID password https://support.apple.com/en-us/HT201487 to recovery these credentials.
If you cannot recover them, then it is unlikely that the device will be of any use to you. In this regard, see Security and your Apple ID https://support.apple.com/en-us/HT201303 (this section Employee privacy and security policies) This section says “without proof of your identity via security questions and other carefully selected criteria, Apple Support can't help you reset a password or perform any other actions on your account.”
Thus, assuming that you cannot recover the credentials mentioned above, I think it is unlikely that you will be able to solve your problem. Still you can try by using the support options below. Be ready to provide any additional information to Apple you think may be pertinent to solving your problem (e.g., your original purchase receipt with the serial number of the device on it).
Get a call from Apple support to help solve your problem using this link https://getsupport.apple.com/?caller=kbase&PGF=PGF63005&category_id=SC0245&symptom_id=23362
Apple ID Support https://support.apple.com/apple-id
Apple ID account security for country-specific and region-specific helphttps://support.apple.com/en-us/HT204169
Get Support: We’re here to help https://getsupport.apple.com/. Go through the options to find the best support option.