"Kira and I talked a lot about raising men that would change the world — and I don't plan to change that goal at all," Charles Johnson tells PEOPLE

Grieving husband and father, Charles Johnson IV, is seeking justice following the death of his wife hours after she gave birth. Along with his mother, TV judge Glenda Hatchett, Charles wants to save other families from the heartbreak his family went through.

On April 11, 2016 — the night before Kira’s Johnson’s scheduled C-section at Cedars-Sinai Medical Center in Los Angeles — the expectant mother decided she wanted to dress up for her baby’s big arrival.

“We were both planning to wear sweats and be very relaxed and casual,” Charles, 36, tells PEOPLE. “But I remember her combing her hair, looking in the mirror and saying, ‘You know what? I want to be really pretty for Langston.’ ”

She went into her closet, picked out a dress, some jewelry and decided how she was going to do her hair.

“We were planning for this to be a big celebration,” says Charles. “But it turned out to be a very, very different outcome than we all expected.”

After her delivery at 2:30 p.m. on April 12, the 39-year-old spent a blissful hour with her newborn and introduced him to his 19-month-old brother Charles V.

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Kira Johnson with baby Langston
| Credit: Courtesy Charles Johnson

But things quickly took a turn for the worse. According to Charles, Kira began suffering serious complications. She began losing color, turned groggy and complained of excruciating abdominal pain. Charles also noticed blood in her catheter. Surgery late that night — long after Kira’s symptoms began — revealed massive internal bleeding caused by a lacerated bladder during her C-section. She died at 2:22 a.m.

Turning Pain Into Purpose

Charles turned his unbearable grief into motivation to hold accountable those he feels are responsible for her death — and to do everything in his power to make sure another family doesn’t have to go through the same horror.

“No one should have to feel this immense pain,” he says. “It’s just not fair.”

On March 22 of this year, Charles filed a ­medical malpractice lawsuit against Cedars-­Sinai Medical Center, claiming that staff didn’t respond to Kira’s symptoms or her bleeding in a timely manner.

• For much more on Judge Glenda Hatchett and Charles Johnson’s story, pick up this week’s issue of PEOPLE, on newsstands Friday.

Although the hospital has not yet issued a formal response to the lawsuit, in a statement to PEOPLE, Cedars-Sinai calls Kira’s death “a tragedy” and says that Charles and Hatchett “are demonstrating important leadership in raising awareness of preventable maternal deaths.”

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Charles V, Charles IV and Kira Johnson
| Credit: Courtesy Charles Johnson

There will be a time one day, says Charles, when he’ll have to have the conversation with his boys about what happened to their mother.

“After that, one of the questions they’ll ask me is, ‘Dad, what did you do about it?’ ” he says. “I owe it to my wife and I owe it to my sons to do everything in my power to make sure that this never happens to another family.”

Charles and his mother are also lobbying in support of new legislation to increase reviews of maternal deaths— which have more than doubled since 1990.

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Credit: Julian Dufort

The reviews, they hope, will help prevent future deaths.

“I don’t want to watch other children not have the love of their mother,” Hatchett, 66, tells PEOPLE. “I must stand and Charles must stand for these families. I don’t want any other husband to go through what my son is going through. I don’t want any other children to ask, ‘Where’s my mommy?’ ”

Adds Hatchett, who has handled countless legal cases throughout her decades-long career: “This will be the most important case I’ll ever be involved in.”

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Langston, Judge Glenda Hatchett, Charles V and Charles IV
| Credit: Julian Dufort

Loss of Love

Even as Johnson watched his wife, whom he says was a “force of nature,” slowly deteriorate in front of his eyes after she gave birth to Langston, he still never thought that he would ever leave the hospital without her.

Kira, a woman who loved fiercely, spoke five languages, raced cars and had a pilot’s license, was also extremely diligent about her health and prenatal care. After meeting Charles in 2005 at a mutual friend’s party, the two fell for each other and dreamed of starting a family — with the hope of having two boys back-to-back.

• Watch the full episode of People’s Features- Judge Glenda Hatchett: Our Family’s Crusade to Stop Maternal Death, available now online on the new People/Entertainment Weekly Network (PEN). Go to PEOPLE.com/PEN, or download the PEN app on your favorite mobile or connected TV device.

“There was nothing she couldn’t do,” he says. “I thought that I was a hard worker until I met Kira. She changed me.

“Kira and I talked a lot about raising men that would change the world and I don’t plan to change that goal at all. I want to make her proud.”