i want to disable 2fa

Can I turn off two-factor authentication after I’ve turned it on?

If you already use two-factor authentication, you can no longer turn it off. Certain features in the latest versions of iOS and macOS require this extra level of security, which is designed to protect your information. If you recently updated your account, you can unenroll within two weeks of enrollment. Just open your enrollment confirmation email and click the link to return to your previous security settings. Keep in mind, this makes your account less secure and means that you can't use features that require higher security.

(from the Two-factor authentication for Apple ID FAQ)

You can log into an iPhone 4 even if two factor is on. Put your password followed by the two factor code into the box where you would normally enter just your password. See the following instructions from Two-factor authentication for Apple ID - Apple Support

If you use two-factor authentication with devices running older OS versions—like an Apple TV (2nd or 3rd generation)—you might be asked to add your six-digit verification code to the end of your password when signing in. Get your verification code from a trusted device running iOS 9 and later or OS X El Capitan and later, or have it sent to your trusted phone number. Then type your password followed by the six-digit verification code directly into the password field.

You're unable to disable Two Factor Authentication when it is on your phone. You shouldn't need it to log into your phone if you have always used the device, it is in place if you're logging in from a new computer and/or a new ip address on your non-Apple device.

Ijustwanttolookattheforums wrote:

That relative would have to share your Apple ID for it to work.

No, they wouldn't. There phone number just needs to be listed as a trusted number. The code can then be sent to their phone via either SMS or voice.

That relative would have to share your Apple ID for it to work.