Sister Charlotte Lange spent months in the hospital after a drunk driver slammed into her car. Her brain was damaged. Her memory and hearing have faded. Her once-curly hair turned straight.

But the 71-year-old nun, who spends about 32 hours a week soothing patients at St. Mary’s Hospital in Richmond, speaks of what she gained that August day in 2010. Now, she said, she brings encouragement learned during her recovery to her work.

“I think I even might be a nicer person,” said Lange, a member of the Benedictine Sisters of Virginia, whose home base is in Bristow. “Not that I want to go through it again . . . but it happened. I think I’m all the better for it.”

On Friday, Carlos A. Martinelly-Montano, 24, was sentenced in Prince William County court to 20 years in prison for causing the crash that also killed Sister Denise Mosier, 66, and badly injured Sister Connie Ruth Lupton, 77.

The case sparked national outrage, becoming a touchstone in the debate about illegal immigration. Martinelly-Montano, originally from Bolivia, had two drunken-driving convictions, and a deportation hearing had been scheduled before the crash. He was convicted of felony murder and other charges.

But for the nuns, the focus has always been on forgiveness rather than punishment. Martinelly-Montano should face consequences, they say. The sisters never liked the politicization of the case and the condemnation of the young man as a murderer for what they see as a terrible accident driven by a sickness with alcohol.

“The way we look at it, it was an accident,” said Lupton, who now lives at the Bristow monastery. “He didn’t plan to get up that morning and do that. He will never turn around if he doesn’t get out and face freedom.”

Or as Lange put it: “But for the grace of God, I could be an alcoholic, and it could have been me behind that wheel.”

Those beliefs come even as the sisters grieve the loss of Mosier, who was known for her effusive personality and love of dancing. A former missionary in Africa, high school teacher and more recently the convent’s spiritual director, she wore flowing gowns of reds and greens, blues and yellows.

“Forgiving would have been so natural to her, she wouldn’t even have given it a thought,” Lupton said.

The women were not in court Friday when Martinelly-Montano stood and told the judge that he has devoted his life to God and the Bible. He said he wants to be a preacher.

“I know this has had an impact on you,” Judge Lon Edward Farris told him. “I know you’ve made changes and great strides, but society has got to be protected.”

On Aug. 1, 2010, the sisters were on their way from Richmond to Bristow for an annual retreat. Lange was at the wheel of the blue 2003 Toyota, Lupton was in the front passenger seat and Mosier was in the back.

It was just after 8 a.m. when Martinelly-Montano, driving a Subaru, swerved into a guardrail and veered into the opposite lane on a narrow, two-lane road in Bristow, crashing into the Toyota.

Now, pins help hold Lupton’s vertebrae together, resembling “railroad tracks,” she said at the trial. She worked hard first to sit, then stand, then walk. Her left thumb was severed, and everyday tasks can be difficult.

Lange said her first days and weeks in the hospital were foggy. A police officer came to express his condolences, saying he was sorry about the lost sister.

How many people were in the car? Lange thought to herself. Then she remembered that she had been told that Mosier had not emerged from the wreckage. At the same time, a memory came flooding back of the night before the accident, when the two were “running around” the grounds of Richmond’s Maymont estate as she showed off her favorite spots.

Mosier wanted to go inside the mansion to have a look around. But they were tired, and there was the trip early the next morning. They would have a look at the mansion the next time Mosier was in town.

“I tell people, ‘She’s in the mansion,’ ” Lange said. “She beat me to it. She got to the big one.”

The Benedictine order has been around for centuries, but Bristow’s version makes for its own kind of Catholic convent. The familiar signs of piety and ritual are there — the arched doors of the church, the cross on the roof. But inside, there is activity and banter. During football season, a large flat-screen TV and comfy chairs accommodate a different sort of Sunday ritual.

The Benedictine sisters seek forgiveness every day, Lupton said. There is imperfection and flaw all around them, and in them. So in the weeks and months after the crash, they let Martinelly-Montano’s family know that they did not feel resentment.

His mother, Maria, who lives nearby, has visited for dinner. Lange said she was pleased to get Christmas cards the past two years from Martinelly-Montano, both apologetic.

Ultimately, the sisters said that Mosier’s death is bearable because they know she is in a better place. Sister Cecilia Dwyer, the prioress, or leader, of the convent, said she believes that it was God’s will when eight women joined the convent in recent months. But she sees Mosier there, too.

“I feel like Denise is up there pulling strings,” she said.