The night after a grand jury declined to indict the white police officer who shot and killed 12-year-old Tamir Rice at a park in Cleveland, Maralee Bradley, a white mother of six, including a 9-year-old black son, slept fitfully in Lincoln, Nebraska.

She and a friend had been talking about Tamir, and the friend asked: “What can we do? How can we help?” Bradley kept waking up, thinking about different pieces of the question.

Thinking about Josh, her adopted Liberian son, hanging out with white friends at a park, about him being the only child of color at another child’s birthday party. “What do I need those parents to be aware of?” she asked herself. “What might feel unsafe to me that they might not know about?”

“I was just thinking we need a level of awareness for everybody involved with my child,” Bradley says.

The next morning, she wrote an essay, “To the White Parents of My Black Son’s Friends,” on her parenting blog. It was heartfelt, unsparing and spelled out things she wanted a small group of people – her son’s teachers, the people who had him in their homes – to understand.

“I’ve been wrestling with talking to you about some things I think you need to know. I’ve wrestled with it because I feel my own sense of shame – shame that I didn’t know or understand these issues before they touched my family. ... I’ve been concerned that you won’t believe me and then I’ll feel more angry than if I hadn’t said anything. But my son is getting older and as he transitions from an adorable black boy to a strong black man, I know the assumptions about him will change. And I need your help in keeping him safe,” she began.

She wrote of the “bizarre balance” of things she and her husband had to tell Josh about the police, how to wear hoodies, and about not sneaking through a neighbor’s backyard during hide-and-seek. Then she asked other parents to do some things.

“As the parents of the white friend of my black son, I need you to be talking to your child about racism. I need you to be talking about the assumptions other people might make about my son. I need you to talk to your child about what they would do if they saw injustice happening.”

If you hear someone call him racist names, say something. Don’t speak black slang around him, trying to be funny. Don’t rub his head because you want to know how his hair feels. Being with Josh “is not time to try out any new risky behaviors.” And if the police approach you, don’t run, don’t leave him alone.

“Literally, I needed 50 people to know this information,” Bradley told me. “But it obviously touched a nerve with a lot more people than that.”

A good post for her usually reaches 15,000 people. By Tuesday, 600,000 people had clicked and hundreds had commented.

In the essay, she urges white parents not to be color blind, which struck many white people as counterintuitive and wrong. But she sees color blindness as a loss and a teaching that doesn’t serve her son.

“We see our kids’ colors, and we value them,” Bradley said. In addition to Josh, she has two biological sons, a Native American son, a Mexican American daughter and a biracial daughter (African American and white). “The reality is the world sees color. ... When our kids are treated differently based on race, we all have to be aware of that.”

It’s something Bradley’s friends have begun coming to terms with. Stephanie Westburg and Bradley often attend church activities together. Josh and Westburg’s daughter, Sophie, 9, have been friends since first grade. Westburg doesn’t follow the news. She knew little of Tamir Rice until Bradley wrote the essay.

She told her daughter: “I want to talk to you about the latest post that Maralee wrote. And it’s about Josh.” His skin color is different, she said, and that means different things to different people. Westburg imagined how people might react if they saw Sophie and a white friend from around the corner playing “Star Wars” – and how they might react to Sophie and Josh playing, especially as Josh gets taller. She talked about people calling Josh names and what Sophie should do if a police officer questioned them. “I told her, ‘Stand up for him and stay with him,’ which are things I’d never thought to instruct my child to do for any other kid.”

Sophie listened quietly. And when Westburg asked how she felt, she cried. “She said, ‘I’m so sad, and I’m so angry,’” Westburg said.

Bradley calls 2015 a year of reading about race and listening to other people’s stories.

In 2016, she told me, she hopes that “white families become aware that black families are having to have these kinds of conversations” and realize “we need to be better advocates for those families and those kids. I have an awareness of how much white families do not talk about race. ... We need to develop a new awareness that this is impacting our brothers and our sisters. This is impacting people that we love. We’re choosing to be unaware, and we can’t keep making that choice.”