I expected him to have some fighting skills after all he has gone through, but seems like he doesn't. That being said, he acknowledges his powerlessness and is working to change it, so it's okay. It's better he didn't just suddenly becoming an asskicker between chapters, anyway.
I have no idea how a letter can shatter anything, though. Maybe the town was taken away from him or something else majorly changing in his life, but so what? He didn't work to make the town a better place for his own glory, he did it to make himself a better person by doing the right thing and taking responsibility. It doesn't matter where he is, he can keep working to become stronger physically and mentally, even if he was kicked onto the streets penniless.