Hi Lawrence2006,
For help with Screen Time, you'll want to make sure the settings are all showing correct with the help of the guide here: Set up Screen Time for a family member on iPhone - Apple Support
You can also check the date and time settings are correct on their device with the steps below found in the article here: If you can't change the time or time zone on your Apple device - Apple Support
"On your iPhone, iPad, or iPod touch
- Make sure that you have the latest version of iOS or iPadOS.
- Turn on Set Automatically1 in Settings > General > Date & Time. This automatically sets your date and time based on your time zone.
- If a message appears saying that updated time zone information is available, restart your device and any paired Apple Watch.
- Allow your device to use its current location to determine the correct time zone. To do this, go to Settings > Privacy > Location Services > System Services and turn on Setting Time Zone.
- Check that your device shows the correct time zone in Settings > General > Date & Time > Time Zone."
Should the issue continue, reach out to Apple Support directly to further assist.
Contact - Official Apple Support
Contact Apple for support and service - Apple Support
Best.