Hi essence295,
Depending on how their location was shared initially you may or may not receive an alert if they turn location sharing back off.
"Stop sharing your location via Find My
You can stop sharing your location with a particular person by choosing that person in the People tab, then scrolling down and choosing Stop Sharing My Location. Or you can stop sharing with everyone by turning off Share My Location in the Me tab.
If the Find My app has been deleted from your device, you can turn off Location Services (go to Settings > Privacy > Location Services) to ensure your location isn’t being shared, then download the Find My app from the App Store again.
Important: If you initially shared your location from iMessage rather than Find My and stop sharing, the person you stop sharing with may receive a banner in iMessage that you’ve stopped sharing your location. If you began sharing from Find My, and then stop sharing your location through Find My the person won’t be able to see you on their list of friends. If you reenable sharing, they get a notification that you’ve started sharing your location with them."
If you believe you should still be able to see his location, we'd advise asking him to turn location sharing off and then on again.
Cheers!