How can we get proof he was ever legally married and if so where and when the divorce was finalized?

My fiance (U.S. Citizen) got married very young to an illegal immigrant here in CA . Her uncles had him sign what he thought to be marriage papers at the church ceremony and she had him sign what he thought to be divorce papers a little over a year after they got married. As strange as it sounds he never thought there was anything strange with the fact that he didn't set foot in a courthouse for either. I recently urged him to get something showing me that the divorce was done&over with but when he went to the court where he thinks she may have filed for divorce they told him there's no record of it. He asked them about getting copies of his marriage license and they needed a case#. He has no case# and really no other information except for her name and D.O.B. Is there ANYTHING we can do?