>>"Convened the Sanhedrin (the highest Jewish religious court / governing body). He had brought before them the brother of Jesus the so-called Christ, who was called James, and some other men, whom he accused of having broken the law, and handed them over to be stoned."
Antiquities, Book 20, 200."<<

Brother of Jesus appears to be a title here. James was apparently the founder of the brothers of Jesus or was a very prominent member and hence was identified as "James the Brother of Jesus" or "James the Brother of the Lord." There is nothing in Josephus's words to indicate that this Jesus was historical. Was there such an order? 1 Corinthians 9:5 would seem to indicate there was: "Do we not have the right to be accompanied by a wife, as the other apostles and the brothers of the lord and Cephas?" Here, "brothers of the lord" is not used as a term for a familial relationship but one associated with apostles and with Peter/Cephas. This savior was also called the messiah by this group but Josephus obviously finds such an assertion dubious.

Why couldn't this still be the brother of a historical Jesus? The most problematic part is that Paul himself writes about his arguments with the "Pillars" of Jerusalem—Peter, John and James—but never quotes Jesus to back up his arguments and never quotes them quoting Jesus. You would think the man that was his actual brother would have had a little something to tell us in that area. Obviously, his word would carry some weight and yet Paul has no qualms about opposing him on issues. And neither apparently resorts to quoting anything from the historical man to back up their arguments. Nor does Paul give any indication that James is related to a historical Jesus other than Galatians 1:19 where Paul's "James the brother of the lord" in the Greek text is disingenuously translated as "James the lord's brother."