GamePass on parent account not appearing on child's account

You should be able to share the game under the Game Pass subscription as long as it meets whatever parental controls you have in place and the Xbox is set to your Home console. The game will need to be downloaded by your account however.

https://beta.support.xbox.com/help/hardware-network/console/my-home-xbox

If you have a child account your parental account should change the privacy settings. If that is not the case check purchases under your account if the membership appears as active.

Hi. My name is Brilliant, an independent advisor. I am happy to assist you today.

Parent and child accounts on Xbox are designed to help parents manage their children’s gaming activities. A parent account is the primary account that can create and manage child accounts. Child accounts are created for children under the age of 18 and are linked to the parent account. The parent account can set up parental controls, such as screen time limits, content restrictions, and spending limits, for each child account.

You cannot change your account to be a child account. You will have to create a new account for your child.

To create a child account, the parent account must first create a family group. The family group can have up to six members, including the parent account. Once the family group is created, the parent account can add a child account to the group. The child account will be linked to the parent account and will have access to the parent account’s Xbox Live Gold subscription and other benefits.

I hope this helps.

You should be able to change the region on your child's account. Try:

1. Sign into family.microsoft.com
   
2. Click three dots for the child's account you need to modify
   
3. Click Manage Consent
   
4. Click Edit this child's personal info
   
5. Edit the country
   
6. Accept the warning about providing consent (steps 7 will do this), the child will appear to disappear from the family.
   
7. Sign in as the child on account.microsoft.com. The child will receive prompt for consent, select "I am the parent" option, sign in with parent account, and then accept consent prompt. Sign into family.microsoft.com (using a parent account), and you'll see the child back in the family.
   
8. Sign back in to account.microsoft.com with the child account to confirm country is now switched
   

Then you should be able to add the funds under the correct currency.

Parental Consent Why you're being asked for parental consent

If the date of birth on your Microsoft account shows that you're under a certain age, Xbox is required to request parental consent for you to use Xbox Live.

If you're an adult, but you got a message asking for parental consent, it's because you're a child in your Microsoft family.

Solution

If you're of an age that requires parental consent, follow the steps on your Xbox to have your parent sign in and add you to their Microsoft family.

If you're over the age requiring parental consent, have your parent remove you from the family. They'll have to sign in to
account.microsoft.com/family, select your profile, and select
Remove.

If you're unable to clear the message, contact Xbox Support.

Related Issues
Parental consent and Microsoft child accounts

Definition of a Microsoft child account

A child's account no longer appears in your family on Xbox One