Money isn't the root of all evil. Love of money is.
I guess he saw Tod save Copper by fighting the bear.
He knew he was in some way important to Copper. He saw it on Copper's face. This is why he lowers his gun and leaves.
Exactly. Copper refused to let him kill Todd. Judas Priest, Iron Maiden, and Metallica love My Little Pony: Friendship Is Magic
He had a change in heart, he saw how strong Tod and Copper's bond was that Copper was actually willing to step in the way.