Setting child Apple ID

See Create an Apple ID for your child. You son will need to have a separate Apple ID.

Once you have done that you can also create a family sharing group to share purchased content.

It is also possible to Use parental controls on your child's iPhone, iPad and iPod touch.

Try adding the credit card number to your Apple ID and then try setting uptake child's ID.

If that doesn't help, contact Apple ID Support for assistance.  See the Apple Support articles below for contact information.  

Apple ID - Official Apple Support.   -

Contact Apple for help with Apple ID account security - Apple Support.  *   (Link doesn’t always load)  

Get Support      -    Work through the screens to get a chat option. You may have to pick a slightly different problem.

Apple Support schedule phone call.   -

Apple on Twitter       

From the Apple Support article below. 

Without proof of your identity via security questions and other carefully selected criteria, Apple Support can't help you reset a password or perform any other actions on your account. These policies are audited and reviewed on a regular basis.

Security and your Apple ID - Apple Support.      *

You are welcome. Contact Apple ID Support.