My response:
Okay, I'll just go with the flow, as it were, and simply answer your question here, rather than in your other post where all the background information can be found about your situation.
The answer concerning the "mechanic's lien" is yes. Or he can take possession of the vehicle, and file a lawsuit to foreclose the lien, thus obtaining an order from the court to sell the vehicle(s) to pay for his services, and costs and fees of court. If there's anything left over, that balance is then paid to the daughters.
I hope those girls realize that they can't register the cars, and they can't get insurance on the cars. That's because the cars don't belong to them. Until there's a Probate action, and court orders received giving the girls ownership, then they are driving illegally - - thus, placing themselves and the Estate in financial danger.
IAAL