Legal Question in Civil Litigation in Georgia

To make a gift of a car he had to put the title in your name. Did he?

If he did and he took the car, he committed a crime.

If he left the car in his name, then you would have a very hard time proving a gift, unless you have some other evidence, and you'd probably lose. Since you haven't told us the details there's no way to answer further.

Bear in mind that lawsuits are expensive, and that a suit versus a parent would guarantee a lifetime familt feud.