Is the room empty? Has he definately gone? Is the car taxed?
If its not taxed, and he s defeintely gone, room cleared etc, she could try contacting the local council and informing them there is an abandoned car. And asking if they will collect. They could come back to her and tell her it is Sorn, so they may not take it. in which case, she may have to contact police and report an abandoned car on her drive.
Aside from all this, i would highly recommend she changes the locks on the main door and the room door, as with the keys, he is a security risk for the other tenants.