Very sad news indeed, and does take the shine off the day.
He would have woken up yesterday morning feeling the same as the rest of us, a bit of excitment and some nerves too, But satisfied that the training had been done and looking forward to a fantastic day.
But its worth remembering that the vast majority ran the the marathon yesterday and came away with nothing worse than stiff legs and a bit of chaffing. Any human activity has its risks, and running is no different, but as tragic as this news is, its is still quite rare in marathons.