Little Boy Blue (1998) on Netflix

19 y.o. Jimmy' s dad is a vicious, impotent Vietnam vet, who forces his wife and son to have incest. He has a secret he'll kill to keep. Jimmy won't abandon his two kid brothers by leaving.

Living in the rural Texas panhandle is a dysfunctional family: Ray, an abusive dad, a Vietnam vet with a war wound that's left him impotent; Kate, a compliant wife and Jimmy, a 19-year-old son, who have an incestuous relationship at the insistence of the dad; and, two small sons who look a lot like their brother. Ray harbors a secret, and he goes to murderous lengths to keep it hidden. Jimmy sleeps out in the shed, has suspicions, but little comes out until Doris, a Yankee woman of middle age comes to town looking for a dead private eye. And why does dad keep calling Jimmy, "little boy blue"?