Hello ThomasPol,
Welcome to Apple Support Communities. If we understand correctly, you do not see your family in the Find My app. Right? In that case, they may not be sharing their location or you may not be following it. Check out the following from Find people and share your location with Find My - Apple Support which helps explain how to do this.
"Ask to follow someone's location
To start following another person, you need to first share your location with them. Then follow these steps:
- Open the Find My app and select the People tab.
- Select the person that you shared your location with.
- Scroll down and choose Ask To Follow Location.
Respond to a location sharing request
When someone shares their location with you, you can choose to share your location back:
- Open the Find My app and select the People tab.
- Under the name of the person who sent you their location, choose Share to let them follow your location.
3. If you don't want to share your location with that person, select Don't Share (or Cancel)."
"Locate a friend
- Open the Find My app and select the People tab.
- Under People, choose the name of your friend who is sharing their location with you.
- Choose Directions to open Maps and then follow the directions to arrive at your friend's location.
If your location appears below your friend's name, you aren't following them. If you see No location found, that person can't be located."
All the best.