When Mack Came Back by Brad Strickland
Maury is terrified when he hears howling coming from the woods. When he goes to see what's making the noise, he finds a shivering dog tangled in blackberry vines. Maury realizes that it's his brother Ben's dog, Mack. Ben gave Mack to a friend before he left for the army, but Mack has come back home. There is nothing Maury wants more than to keep the dog that once belonged to his brother. But Maury's father sees Mack as a constant reminder of his eldest son, who abandoned the family farm to go fight a war. . . .
New York: Puffin, 2000