I am one who buy into the tradition that Joseph had children from a previous marriage, asthe bible doesn't tell us this, but I don't normally make it a point of division either, BUT....
You state that these older brothers were half brothers (according to tradition). How can they be older half brothers? If these brothers are from a previous marriage of Joseph, the only way they could have a blood relationship with Jesus would be for Joseph to be the biological father of Jesus (Thus dening the divinity of Christ).
I take it you meant that these were step brothers, not biological half brothers.... Also, scripture tells us that Jesus had not just brothers, but also sisters:
Is not this the carpenter's son? is not his mother called Mary? and his brethren, James, and Joses, and Simon, and Judas? And his sisters, are they not all with us? Whence then hath this man all these things?
- Matthew 13:55-56 (KJV)
OK, I guess I'll get flamed, but I actually enjoyed the book.