Apparently I've not made myself clear on this. Jacob (Anglicized as James), was born of Mary's womb subsequent to Jesus, therefore a son of Mary therefore a brother of Jesus. That's what I have called a womb-brother, not as a fraternal twin, as your impression seems to indicate.
Paul met Jacob THE brother of THE Lord. Not A brother in the Christian sense, or a cousin in the larger family sense.
Jacob/James was born of Mary.
Perpetual virginity is a figment of the imagination of someone whose thesis would be destroyed if Joseph and Mary followed their marriage vows and God's command to be fruitful and multiply. If Joseph was not the loving husband of Mary expecting to enjoy connubial bliss following Jesus' birth, what function did He have in God's plan? To use up plaster of Paris for future illustrations? /s
Also, get this, I'm not gonna be your pet project going forward in this thread.
You have entered no proof, just a modern opinion, that as far as I can tell, did not originate until the progressive devolution of Protestantism in the 19th Century, the same century in which some Protestants devolved and originated Mormonism.
Your opinions do not make facts.