How to remove an old family member

Here are the instructions on how to remove someone or remove yourself from a family group https://beta.support.xbox.com/help/family-online-safety/child-accounts/remove-family-member

Hello sir. You could keep all the membership yourself by removing profiles in the plan. This can be done by following this steps:

Console steps: Remove a member from a Gold Family Pack

On your console, sign in to Xbox LIVE with the primary account for the Gold Family Pack.

Go to Settings, and then select Family.

Select the member you want to remove from the Gold Family Pack.

Go to Account Management, and then select Remove From Gold Family Pack.

Follow the on-screen instructions to remove the member from the Gold Family Pack. When prompted, confirm the removal.

Computer steps: Remove a member from a Gold Family Pack

Go to the Family Center.

Hover over a family member, and then click Remove from Family.

Hi and thanks for reaching out. I hope you’re doing well. I'm an Independent Advisor and a Microsoft user like you and I'll be happy to help you.

I understand you wanted your son to play his game Minecraft. As per the error you're receiving, family members under statutory age need an adult's consent to join a family group and he needs to be in a family group. In this case, you need to manage his account restrictions by changing his Privacy Settings at https://account.xbox.com/en-us/Profile?xr=mebar....

Once you're on the Privacy & Online Safety page, you should be able to see his account. Please click on it to change his Privacy Settings. Make sure that all settings under the Privacy tab and Xbox One/Windows 10 Online Safety are set to "Allow" or "Everyone". It should be like the screenshot below.

Also, make sure to set these settings to "Allow" or "Everyone".

- You can see and upload community creations

- You can communicate outside of Xbox Live with voice & text

- Others can communicate with voice, text, or invites

Additionally, if he's playing on an Xbox console, make sure he has an active Xbox Live Gold or Game Pass Ultimate.

- Press the Xbox button on your controller to open the guide, and then select Profile & system > Settings > Account > Subscriptions.

http://support.xbox.com/en-US/billing-and-subscriptions/parental-controls/managing-family-members#9bbb75968bc4439da8b0b887b2aeb705 shows
how to remove yourself from the Family Plan.

See here for instructions on how to remove a child account from your family: http://support.xbox.com/en-US/xbox-one/security/remove-family-member

Keep in mind that after the child account is removed, it will not be able to use Xbox Live until they are added to another family account.