Factory reset

The person setting up the restriction passcode is the only one that will be able to deal with it. On the Apple ID issue,

See If you forgot your Apple ID password https://support.apple.com/en-us/HT201487

You also can use Having trouble signing in/iForgot https://iforgot.apple.com/password/verify/appleid 

And you undoubtedly will need to see If you forgot the answers to your Apple ID security questions https://support.apple.com/en-us/HT201485

Before trying to answer your security questions is very important that you think about your questions and their answers carefully and try to recall all details you can. If you don't answer them correctly enough, then you easily can lose control of your account.

For the restrictions passcode, if running IOS 13.4 or above, use the article below.

Screen Time passcode reset

If using an older IOS version, you will need to restore the device to factory settings. Do not restore from a backup made when the Screen Time code was active.

Restore to Factory setting.      

Backup - Restore your device from an iCloud or iTunes backup.