|Q. Was Jesus’ brother Judas the same Judas who betrayed Jesus for silver?|
No, the two men are not the same. In New Testament times, people did not have last names, but individuals were identified by their father’s name or by the city or region they came from, and that enables us to identify these as different men.
The Judas who betrayed Jesus is called Judas Iscariot, most likely meaning that he was from the village of Kerioth. Hebrew or Aramaic “man of Kerioth” would be ish-Kerioth, and English Bibles present a Latinized version of that name, Iscariot.
The Judas who was the brother of Jesus came to believe that Jesus was the Son of God and the Messiah, and he actually wrote one of the books of the New Testament, the epistle of Jude. In that book he identifies himself as “the servant of Jesus Christ and the brother of James.” James, another brother of Jesus, was the leader of the church in Jerusalem, and at the time when Jude sent out his letter, identifying himself as the brother of James was a clear way for Jude to let his recipients know specifically who he was.
(Jude and James were actually half-brothers of Jesus. They had the same mother, Mary, but they were sons of Joseph, while Jesus was the Son of God.)