When the NT speaks of Christ's half siblings, we trust that Scripture said what it meant and meant what it said. We don't slip and slide and shuck and jive trying to come up with rationalizations for alternate words. The languages were quite robust enough to distinguish between siblings, cousins and uncles. The text mentions siblings. End of story.
It doesn't say half-siblings.
Other than Mary visiting her "cousin" Elizabeth, I don't think I've ever seen the words "aunt, uncle or cousin" in the Bible....am I wrong?
Catholic Bibles smell funny.