Find my phone

Sharing location is directional. If you share your location, you cannot find your family member’s location unless that family member shares it. And if the member chooses to share it, the location cannot be updated if her/his device is turned off.

You can’t see them at all unless they shared their location with you. Sharing your location with someone does not let you see their location, unless they reciprocate. And if their location is not turned on then you can’t see where they are.

You cannot track a phone that isn’t powered on. If that isn’t what you are asking please clarify.