When the novel opens, Silas is in a bad state: his friend and fiancée have betrayed him, and he's been kicked out of the only home he's ever known. Godfrey is a kind of shadow protagonist; Eliot doesn't spend as much time on him, but he does have a similar plot arc. His falling stage, which takes place off-stage, begins when Dunstan somehow convinces him to marry the unsuitable Molly.
All we hear about Godfrey is that the villagers have noticed he's been running a little wild, but Eliot treats us to page after page of Silas's distress. It is so intense that he loses his faith in God, and we almost lose our patience with the narrator.
Again, we hear lots and lots about Silas's imprisonment in his endless round of weaving and hoarding. Eliot actually describes his soul has having been "long stupefied in a cold narrow prison" (1.14.35). Godfrey, meanwhile, is trapped by Dunstan's blackmail: he can't confess his marriage to his father because he's afraid he'll be disinherited, and so he has to follow Dunstan's orders.
Just when it can't get any worse, Silas's money is stolen. He gets glimmers of a feeling that maybe this would be a good time to start participating in village life, but he just can't bring himself to do it. He hits rock-bottom at Christmas, sitting alone in his cottage. Godfrey, meanwhile, pursues Nancy recklessly, and his nightmare is occurring without his even being aware of it: Molly is making her way, with their child, to force him to acknowledge them.
But Molly never makes it, and Silas adopts Eppie. A little child saves him (don't they all?). She connects him to his community, gives him purpose, and basically brings him back to life. Godfrey? Not so much. By finally acknowledging his daughter, Godfrey manages to salvage what's left of his character. He finally accepts responsibility and grows up. But he doesn't get Silas's happy ending.