two factor auth turned on by itself

It can only be turned off within 14 days of having been enabled using the link in the enrollment confirmation email.

Kerellian wrote:

2 factor makes it harder for my autistic son to use the Ipad when ever he wants .

Why does it make it hard for him to use the iPad? Once logged into the correct Apple ID on an iOS device, you will rarely ever need to interact with 2FA. If you explain when you're seeing it happen, perhaps someone can give you advice on how to set things up so that doesn't happen.

You should also set up a phone number (can be landline or mobile) as a trusted number in the even that something happens to the iPad.

Two-factor authentication for Apple ID - Apple Support

That would indicate that someone signed out of their Apple ID.

You might want to look into the parental controls available.

Use parental controls on your child's iPhone, iPad, and iPod touch - Apple Support

Apple 2FA has nothing to do with the device itself. You can change settings all you want as 2FA has nothing to do with that. It applies to using your AppleID login with Apple online services.

On a device, for things like iCloud, messages, FaceTime, the App Store etc a 2FA code is only needed if the AppleID used is not already signed into those services on the device. Once initially signed in, as long as you don’t actively sign the AppleID out, a code is not needed again.

And it is required if you use any one of several online services, including Apple Pay, iMessages in iCloud, iCloud Keychain, HomeKit.

Kerellian wrote:

when it does an update for some reason it triggers the two factor. He is not old enough to deal with the two auth and it causes major issues with him.

No, updates don't cause the need to use 2FA. He would only need to use 2FA if he signed out of the Apple ID the phone is tied to and tried to sign back in, either with that one or another one or if he tried to sign into an Apple service using a browser that wasn't marked as trusted.

Updates will require the device's log in passcode once they finish installing and the device restarts. Disable auto-updates so that you can be in control of when that happens.

What issues is it causing him to use the iPad? What is he signing in and out of with his AppleID that triggers the need for a code?