Yes only the authorized owner of the car can see the car normally. The owner has to contact Tesla to give permission to have the car appear on their phone’s app. Not sure exactly what the procedure is these days as my husband’s car was added to my newly set up account in 2017. When I got my car I had to give Tesla permission to add my car to my husband's app. Along those same lines when my husband ordered our solar system on his account, after getting PTO (permission to operate by utility) he contacted Tesla to allow me to access our solar system on my phone.
For us it took a few days the first time to get the account info updated, but for subsequent requests it happened much quicker.