As cynical as I can be, I truly believe that people want to do the right thing if presented the opportunity.  The average person is not evil.  I have found that runners are extraordinarily giving people. 

Running 26.2 is a bear.  And as you're training, there are some seriously bad low "I can't do this" days.  There are LOTS of those and when you're pounding out the miles training, there is room for self doubt if you let the seed set in.  For me, my tshirt says it all, "You think training for endurance event is hard, try chemotherapy".  It got me through some tough days.  (And you know how I struggled.)  Seeing a man like Mr. Kuhn, just adds to the inspiration.  You think to yourself, "I think I'm digging deep?  Please.  I cannot fail. If this man is so determined, then I can too..."  You want to be a part of that positive energy.  That's what it is... he isn't even running for himself, which makes it even BIGGER. 

As I was training, real runners would come to me and say, "What you are doing is so selfless. I have so much respect.  You are not running for you... but for someone else."  Not only is this man running blind, but he is running for a charity. 

They don't make many men like him.  I strongly suspect he will make an impact on many lives during that marathon.