Forgotten passcode

Click on this link to read what to do "If you forgot your Apple ID password" - https://support.apple.com/HT201487

or go directly to this link --> http://iforgot.apple.com/

Also read about "What to do after [or before] you change your Apple ID email address or password" - https://support.apple.com/HT204071

If you still need help:

Contact Apple for help with Apple ID account security "This article provides country-specific Apple Support contact information for customers seeking help with their Apple ID password or other security-related issues." - https://support.apple.com/HT204169

You mentioned she forgot the passcode. Did she forget the device passcode and the password to her Apple ID?

Passcode - If you forgot the passcode for your iPhone or your device is disabled.      

Passcode - If you forgot the passcode for your iPad or your device is disabled.     

Passcode - If you forgot the passcode for your iPod Touch or your device is disabled.