Hi Epicmanchildz,
For help with using the downtime feature on iOS, test the steps below to ensure the setting on both devices are correct. You can also find those steps in the article here: Set up Screen Time for a family member on iPhone
"Set downtime and app limits on a family member’s device
- On your family member’s device, go to Settings
> Screen Time. - Tap Turn On Screen Time, tap Continue, then tap This is My Child’s iPhone.
- To schedule downtime for your family member (time away from the screen), enter the start and end times, then tap Set Downtime.
- To set limits for categories of apps you want to manage for your family member (for example, Games or Social Networking), select the categories.
- To see all the categories, tap Show All Categories.
- Tap Set, enter an amount of time, then tap Set App Limit.
- Tap Continue, then enter a Screen Time passcode for managing your family member’s Screen Time settings.
Note: You can also turn on downtime on demand for a family member, either directly on their device, or through Family Sharing on your device (if you’ve set up Family Sharing).
If your child requests more screen time, you can approve or decline the request in Settings > Screen Time or in Messages."
You can also find helpful information here: Set up Screen Time for yourself on iPhone
If the issue remains, have your mom reach out to Apple Support directly to report the issue and check on some additional settings.
Contact - Official Apple Support
Contact Apple for support and service - Apple Support
Cheers.