that is neither up-casing nor-downcasing, but (de)capitalization, which is a significantly more complex task (which ultimately requires up- or down-casing, but a whole lot more before then).
I am not aware of a Unicode concept of "the latin letter o followed by an apostrophe followed by another latin letter". Unicode would identify the glyphs for such a concept, but I don't see how Unicode is involved in this in anyway as far the process of deciding what "capitalized o'reilly" means.
