What is a hero? The dictionary defines it as someone, who does great and brave deeds and is admired for them. Both Atticus Finch and Grant Wiggins are heroes, but in their own, distinguished way. Both of them possess noble qualities, but only Atticus shows them all the time. Courage, Wisdom and Personality are the factors that define heroes. Grant however shows these qualities only sometimes; he switches back and forth. That makes him a "human" hero rather than a superhero, who shows them all the time like Atticus. He, unlike Grant, is characterized by his absolute consistency.
Courage is a factor that defines Atticus. You can observe this in many parts of the book including the part where he's willing to defend Tom Robinson and explains his reasoning as "simply because we were licked a hundred years ago before we started, is no reason for us not to try to win!" (pg.76) But he also teaches his children, especially Jem, that courage doesn't mean just using guns or killing a rabid dog. "I wanted you to see what real courage is, instead of getting the idea that courage is a man with a gun in his hand." (pg.112) Grant however has courage, but chooses not to display it all the time. He wants to move out of the country throughout the whole book, because that would be his way of escaping all of life's problems and not facing them like a man. That's a sign of cowardice. "If you"d just say the word, I"d drop everything!" he says to Vivian. (pg.113) But before that he defends Vivian in front of his aunt and stand up for her: "This is the woman I"m going to marry, so you might as well get along." (pg.113) Not that it just proves there's courage in him, but it also proves that he is not consistent in his actions. Both Atticus and Grant possess intelligence and wisdom. The difference is that one uses it to teach his children and the other uses it to help a poor, black man, who's about to die, understand the world.