How to Fix Find My Location Sync on MacBook?

It's great that you've already tried signing out and back into iCloud and checked the settings between the devices.

Here are a few more steps you can try to troubleshoot the issue with 'Find My' on your MacBook:

1. Sometimes a simple restart can resolve syncing issues. Restart your MacBook and check if the location updates start working.
2. Ensure that your MacBook has a stable and active internet connection. 'Find My' relies on an internet connection to update locations.
3. Confirm that Location Services are enabled on your MacBook. You can check this by going to System Preferences > Security & Privacy > Privacy > Location Services. Make sure the checkbox for "Enable Location Services" is ticked, and also ensure that 'Find My Mac' is checked in the list below.
4. Sometimes, security settings or firewall configurations might interfere with location services. Temporarily disable any third-party security software or firewall and check if the location updates.
5. If the issue persists despite trying these steps, it might be worth reaching out to Apple Support. They might have additional troubleshooting steps specific to your setup or be able to diagnose any underlying issues.

These steps should help pinpoint and potentially resolve the issue with the location not updating for one of your kids' iPhones on your MacBook's 'Find My' app.