He somehow got a drivers license, and that is a key document in this country. A birth certificate can be forged.
While it can, such would not be necessary to get a DL, there is no "natural born citizen" requirement to get a DL, and the DL does not say *where* one was born. I doubt they even look at the "where". And once you get one, you don't have to submit the BC for subsequent ones. Who would have cared 30 or so years ago, where one "Barack H. Obama" was born when he got his first DL.