[quote="endaman, post:1, topic:346697"]
I'm sure this has been asked before but I could not find in search so...
9 but did not set eyes on any of the rest of the apostles, only James, the Lord's brother.
Does Paul mean James to be a blood brother or a spiritual brother?
He wasn't a blood brother through Mary if that's what you're asking. One of the ways we can know this (besides the fact that the Church infallibly teaches it.) is in the list of the apostles given in the Gospels, there are two James' named, and both of their father's are named as well. One is named Alphaeus, and the other is Zebedee. Neither is the son of Joseph, who was Mary's husband. So he can't be a blood brother in the immediate sense.
But, he seems to be more than merely a spiritual brother, because Paul singles out James from Peter as the Lord's brother. If all that was meant was a spiritual relationship, then wouldn't Paul have called both Peter and James, "the Lord's Brother?" That's why I tend to think he was some sort of blood relative to Jesus.
Like some other posters have pointed out, adelphos had a wide meaning. It could mean brother from the same parents, or it could be another relative, or no physical relation at all. I already pointed out why I think there is some sort of family relationship between James and Jesus. But what that is is not entirely clear. We know he's not a brother of The Lord through Mary or Joseph. It's possible he was some kind of cousin.
That seems most likely given the reference in John 19 to Mary the mother of Jesus' sister (also named Mary) being with her at the foot of the cross, which, when we cross reference that with Mt 27:56 we see this Mary was called the mother of James and Joseph. It's hard to tell if this is the same James that Paul met, but if it is, then that would make James at least a first cousin of Jesus.
All that was a long way of saying we don't know exactly James relationship to Jesus. :) But we do know he's not a brother through Mary and he also seems to have some sort of physical relationship to Christ that Paul felt was necessary to single out.