'Activation Lock for iPhone, iPad, and iPod touch' is a security feature that's designed to prevent anyone else from using an iPhone, iPad, or iPod touch, if it's ever lost or stolen. To learn more click here --> http://support.apple.com/HT201365
For an individual to remove an activation lock absolutely requires the information for the account that applied the lock. Click on this link to learn 'How to remove Activation Lock' --> https://support.apple.com/HT201441
In your case you are also seeing an Apple ID is locked or disabled "for security reasons" message. Click here and read what to do --> https://support.apple.com/HT204106 If you or someone else enters your password, security questions, or other account information incorrectly too many times, your Apple ID automatically locks to protect your security and you can't sign in to any Apple services.
Also note "What to do after [or before] you change your Apple ID [email address] or password". Click here --> https://support.apple.com/HT204071 - "After you change your Apple ID email address or password, you might need to update your sign-in information with any Apple services you're using."
Recover your Apple ID when you can’t reset your password - "If you use two-factor authentication and can’t sign in or reset your password, you can regain access after an account recovery waiting period." - https://support.apple.com/HT204921
If you cannot resolve it yourself try one of these contact methods:
- Click here --> https://support.apple.com/choose-country-region/ Select your country, then a product.
- Contact Apple for help with Apple ID account security - https://support.apple.com/HT204169
- Contact Apple for support and service - "See a list of Apple phone numbers around the world." - https://support.apple.com/HT201232
Apple can completely reset a device if a person can provide sufficient evidence of valid ownership. Do this online at: Activation Lock support request - https://al-support.apple.com/#/additional-support Apple says, "Proof of ownership documentation is required," but does not state what currently constitutes proof. Prior to this new online service Apple typically required the original receipt issued by an Apple Authorized dealer and documented provenance (so typically it would be the original owner who does this, or a descendant with legal proof of ownership).