It is best to start by looking at St. John 19, 25. There it is evident that the Virgin Mary had an older sister whose name was also Mary: “Meanwhile, standing near the cross of Jesus were his mother, and his mother’s sister, Mary the wife of Clopas, and Mary Magdalene.”
Turning next to the Gospel of St. Mark 15, 40, speaking on the same point: “There were also women looking on from a distance; among them were Mary Magdalene, and Mary the mother of James the younger (Less) and of Joses (Joseph), and Salome.” Who is this “Mary the mother of James the younger and of Joses?” Of the Marys mentioned in St. John 19, 25 it must be Mary the wife of Clopas, not Mary the “mother of Jesus,” as the Virgin Mary is never mentioned by any other title except as “mother of Jesus.” Further, we know that the father of James the younger was Clopas, the husband of Mary of Clopas (St. Mark 3, 18), making Mary of Clopas James’ mother. As for Jude, he was also a son of Clopas and the Virgin Mary’s sister as Scripture speaks of him as a brother of James the younger: “James son of Alphaeus (Clopas), and Simon the Zealot, and Judas the brother of James” (Acts 1, 13 [Douai]). Consequently, Our Lord had cousins by the names of James, Joseph and Jude.13
One can safely state then that the “brothers” of Our Lord as mentioned in St. Matt. 13, 54 -57 being James, Joseph, Jude etc. are in fact the same James, Joseph and Jude just determined to be His cousins. This was St. Jerome’s assertion in the early fourth century:
"Suppose that the Brethren of the Lord were Joseph’s sons by another wife. But we understand the Brethren of the Lord to be not the sons of Joseph, but cousins of the Saviour, the sons of Mary, his mother’s sister."14
St. Augustine was no less strident in his defence of the Virgin Mary’s perpetual virginity:
"It is written (Ezekiel 44, 2): ‘This gate shall be shut, it shall not be opened, and no man shall pass through it. Because the Lord the God of Israel hath entered in by it…’ What means this closed gate in the house of the Lord, except that Mary is to be ever inviolate? What does it mean that ‘no man shall pass through it,’ save that Joseph shall not know her? And what is this -‘The Lord alone enters in and goeth out by it,’ except that the Holy Ghost shall impregnate her, and that the Lord of Angels shall be born of her? And what means this - ‘It shall be shut for evermore,’ but that Mary is a Virgin before His birth, a Virgin in His birth, and a Virgin after His birth."15
It would be forcing credibility to believe that the Virgin Mary and Her older “sister” both had the same names and also had children with the same names. One can expect, also, that after St. Joseph died the Virgin Mary would have gone with Our Lord to live with or nearby Her older “sister,” explaining why She was travelling with those mentioned in St. Matt. 12, 46. It is a clear example of the word “brother” being used to refer to a first or second cousin.
It is also important to examine closely three major events in Our Lord’s life referred to in the Gospels: (i) the return of the Holy Family from Egypt to Nazareth after the death of Herod; (ii) the finding of the Child Jesus in the Temple of Jerusalem after being lost for three days; (iii) Our Lord giving His Mother to the care of St. John at His crucifixion. Our Lord, according to tradition, was 10, 12 and 33 years of age respectively when these events occurred. Yet, never is there any mention of brothers or sisters of His being present, which one would naturally expect if they had actually existed.16
theworkofgod.org/LIBRARY/Apologtc/R_Haddad/4dgmMary.htm#Perpetual%20Virginity
I also like to add that there is no Hebrew or Aramaic word for cousin, so brothers and sisters were used instead. Joseph and Mary only had one son, and He is Jesus. There no other children after Mary gave birth to Jesus. This is fact. This is history.
Jesus is using mary as a model of faith. And God the father, he is also a model of faith. And all of mary’s other sons, they are also models of faith.
