"Jack had another son who committed suicide because he was strung out on drugs," said Barens. "He was out drinking with buddies and overheard one guy brag how he made money selling drugs to kids. With his mental frame of mind as a soldier, he thought of the guy as scum and had to kill him."
Hall says in the film that he had been "trained" to kill in hand-to-hand combat as an Army Ranger.
"And when he came back from the war, they gave him a carton of Lucky Strikes and fifty bucks," said Barens. "Jack tumbled into alcohol and was destroyed by the Army. He was damaged goods."
Iowa State's 30-year nurse administrator Marilyn Sales told ABCNews.com that the film "brought tears to my eyes."
She launched the hospice program in 2006 with a handful of inmate volunteers. At first, they were resistant to the idea, but soon they "put their heart and souls into it."
"I called the cell house and asked them to send over five lifers who were trustworthy," said Sales, 69, who is now retired. "I knew it wouldn't work without the inmates. They came over grumbling, then we popped the ["Angola Prison Hospice"] tape in and there were just tears."
When she asked if they could handle it, three said yes. "For two of them it struck too close to home," she said.
"I knew that without them, we couldn't have a viable hospice program," said Sales. "I didn't want it to come from outside the institution."
Hospice volunteers get a 14-week training course, learning "assistance in daily living." They work as orderlies in the 12-bed infirmary, change bedding, providing companionship, delivering food, and feed the ill and injured. Two of the rooms are reserved for the dying who receive 24/7 personal care and unlimited access to family.
"I think it's their way of giving back," she said of the volunteers.
The program is financially self-sufficient with furniture made in the prison workshop. Local hospitals donated beds and quilts and other bedding provided by a local church. Lap blankets were knitted by a women's group. The inmates themselves buy videos for the hospice program.
Dying men like Jack Hall deserve the dignity of hospice, Sales said.
"Jack was a cantankerous old coot for years," she said. "Jack was Jack and couldn't help [but] like him. His reason for a life sentence was very compelling. He righted what he saw as a wrong."
Hall spent about six weeks in hospice, the only patient during most of the filming. Then a second prisoner, a 45-year-old dying from ALS, or Lou Gehrig's disease, was admitted, but he was not part of the documentary because he was unable to speak.
Sales answers critics who say those who have committed violent crimes don't deserve compassion: "We have to be better at caring and compassion for people," she said. "They are paying the price by being in prison. They can't choose what they eat, what they wear, when they go to bed and when they wake up. When the gavel drops, it's a life sentence. It's over."
Sales said hospice should be mandatory in all prisons.
"I am not the judge and jury," she said. "There but for the grace of God go I. One bad decision, one stupid mistake and you are there for life. No one should die alone."
"Prison Terminal" will have its world premiere at the Irvine International Film Festival in California. Oscar nominations come out Jan. 16.
Edgar Barens is currently a media specialist at the Jane Addams College of Social Work at the University of Illinois.