If you want to really shine on the next WC party, you can always try to perplex people by telling them that the latin root of corps and corpse is the same, i.e. 'corpus'. Which just means 'body', in any form, either organizational, natural, alive, dead, with fries and without.
To quench the quickly spreading silliness, something more to the point: Posthumous promotions in general seem to be rather customary in "lower" ranks (NCO's). That may be the cause to let Blair be what he was, apart from the nostalgic "be remembered as in life" aspect, and the not so nostalgic "don't confuse the player and spend the budget on military pathos" aspect.