Hello Paul Jeanneret
I can see that you are having issue with Microsoft Family safety
The most likely reason the child is missing from Manage consent is that consent was originally provided by another adult or through a different Microsoft account. Being the current family organizer does not automatically provide permission to withdraw consent granted by someone else.
Here are what you can try:
- Sign out of all Microsoft accounts in your browser or open a private browsing window.
- Sign in to Manage permissions using each adult Microsoft account that may previously have approved the child.
- When the child appears, select Remove consent for this child’s account.
- Return to the Family Safety page, select the child, and choose Remove from family group.
If the original consenting account cannot be accessed, try recovering that adult account first.
I hope you’re able to get the child account unstuck soon.
Feel free reply back to this post if you need further assistance, I'll be happy to help.