You are correct, Nobel prizes are not awarded to the dead, unless they die just after announcing the prize and before the ceremony (http://www.guardian.co.uk/science/2011/oct/03/nobel-prize-aw...). Gandhi was denied the prize for this reason.

In this case, it is simply the post title being misleading, as it's not the Nobel prize these folks won, but the Nobel memorial prize in economics, which is a relatively new prize which is not part of the 5 Nobel prizes which had been given by Nobel's estate for more than a century.

Edit: oh I see they didn't reward a dead in this case, misread your comment..