While arguing about logical fallacies you've failed to address the original point entirely; A sample size of one is a problem, guys. It can't disprove the null hypothesis. It doesn't matter how many observations you make in the control group; At the very best, the ideal case, you'll succeed in identifying properties of this brain not present in all those other brains, but what you could be identifying may have absolutely nothing to do with intelligence. It could just as easily be another property, like his love of Justin Bieber (hey, if we're going to allow a sample size of one to be scientifically valid, I'm bringing time travel back -- so no bitching).
But the sample size it not 1. The article is claiming two things: CC thickness is correlated to Intelligence (which the article should have backed up with references), and two: Einstein's CC was thicker then normal. It is thus drawing a rather thin correlation to a correlation. But the sample size is not 1 because the article is not trying to say that since Einstein had a large CC and was intelligent, then CC thickness must mean higher intelligence.