Then something is very, very wrong. As I said the only location that is shared is the one from the device that has the active location sharing in the Find My settings and only when you actively share it.
All other devices cannot and should not appear on anybody else's Find My screen but your own unless you share an Apple ID.
When. sharing location with Family Sharing the map should only show the Person's picture and not individual devices:
I would check the iCloud account being used on your devices and your sibling's devices to make sure they are not the same.
Also how are you seeing your devices on your sibling's devices exactly? Where are you going to, or what App are you opening to see them on your siblings device?