What is the main conflict in The Tie That Binds: A Novel by Kent Haruf?

As the story opens, Sanderson Roscoe is inside a corral working with cattle when a man who is dressed in yellow pants arrives. Sandy notes that the man can't figure out how to open the gate and climbs over, though his weight is not good for the gate. The man then tells Sandy that he's from the Denver Post and he's come to ask some questions about Edith Goodnough. Sandy notes that the reporter knows about the barking dog and the chicken feed and that he, Sandy, had tried to keep the firefighters from entering the Goodnough home on the night it burned. He then says that there was much more of the story they didn't get right, and that he wasn't about to tell them anything. He was willing, however, to tell the story as one friend to another over a cup of coffee. The story, Sandy says, goes something like this.

Ada and Roy Goodnough arrive in Colorado as homesteaders and take up a section near the one being farmed by an old woman and her six-year-old son, John Roscoe - Sandy's father. Roy is downright mean and strict and it's John's mother, Hannah Roscoe, who helps Ada deliver two children, a daughter named Edith and a son named Lyman. Life for the family is hard with Roy refusing to spend money on anything that isn't absolutely necessary. Ada dies when Edith is just seventeen and Roy informs her that she's now to take on her mother's duties. One year, John is helping with harvest when Roy gets wire tangled in the equipment and his yelling spooks the horses so that they jerk ahead, catching Roy in the machinery and grinding both hands to nubs. With one finger intact, he is able to button his shirts but is mostly dependent on Lyman and Edith and that dependency weighs on the two. Then John asks Edith to marry him. She realizes she can't leave her father but Roy, fearing that she might, rigs an axe over a rafter and chops off his remaining finger.