I mean, if Tesla thinks the guy is the owner, then he should be able to know where it is and control it. If he was no longer the owner, they should have updated that with Tesla.
It's not about who is the owner. They both were. It's about the fact that Tesla only supports having 1 owner, and the husband set himself up as the owner and added the wife as an additional driver.
Honestly, I don't see a good way out of this without adding a feature that only the profile that unlocked the car last being able to see where it is. That's not a feature they have, nor are legally required to provide.
Usually in cases like this the court looks to who makes the payments. He may be co owner but if he hasn't made any payments since separating and hasn't used the vehicle it isn't his.