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Mountainside, New Jersey (CNN) When Tracy Crosby's husband died unexpectedly, she suddenly became a single mom to four young children.

"The hardest thing in the world is to tell your children that they're never going to see their other parent again," she said.

Her children would cry a lot at bedtime because they missed their dad. Crosby worried about how they would cope long-term.

To avoid that fate for her kids, each month Crosby takes her family to Imagine, A Center for Coping with Loss , where they learn how to deal with their grief with other children who have lost a parent, brother or sister.

"It's really nice to have people listen to you who actually understand what you're going through," said Crosby, who has been going to Imagine for a year and a half. "It's huge to have that support system."

Mary Robinson founded the nonprofit in 2011 to create what she didn't have after her father died from cancer when she was 14. As a result, her grades dropped, she quit her activities and became withdrawn.

Mary Robinson founded the Imagine center to help kids deal with grief.

"It looked like bad behavior ... But it was a textbook example of a grieving child," Robinson said. "I wasn't a bad kid. I was a sad kid."

Robinson struggled until she got help in her late 20s. Eventually, she began volunteering at a children's grief support group and nearly two decades ago, she quit her job to devote herself to the work full-time.

"I really do this work to make sure other kids don't lose years of their life to unresolved grief," she said. "The death of a parent is really a trauma for a child. But it doesn't have to leave a child traumatized if they get support."

Pizza, talking sticks, and a 'volcano room'

At Imagine, support starts with a pizza dinner, giving everyone a chance to socialize. Then family members and volunteers form a circle and pass around a "talking stick," introducing themselves and saying who they've lost.

"Naming the loss is actually an important part of mourning," Robinson said. "It also normalizes your loss and your grief. So, kids see that every single person has had somebody who died. And that's incredibly powerful."

The gathering then breaks up into age groups. Through games or arts and crafts activities, like making Memory Boxes, children and teens are encouraged to open up and share with the volunteer facilitators. A realistic hospital room gives children whose parents suffered long-term illnesses a unique way to work through their feelings, while others let off some steam in the "Volcano Room" with its padded walls, pillows for punching and books for ripping.

The center's volcano room lets kids express their emotions.

"It's a place for kids to come and erupt like a volcano," Robinson said. "It's a safe way to release their angry feelings ... and it makes it easier for kids to talk and express themselves."

Parents also support each other and learn ways to help their children mourn.

"They know (their kids) have entered this new at-risk category, so they're wondering 'What do I do?'" Robinson said. "So, we say, 'Here's simple ways to listen that help kids open up and here are ways to be a role model for how to cope.'"

At the end of the night, everyone holds hands in a circle and a squeeze makes its way around one by one. The experience leaves Crosby and her children feeling positive.

"They're always so excited to go," Crosby said. "To know that they're so happy, and they have the opportunity to talk about their dad ... it makes me feel like I'm doing the right thing."

"My priority is that I raise happy, emotionally healthy children ... and Imagine can help me do that."

Loss is part of life, but nobody teaches us what do you do when you have all these feelings. CNN Hero Mary Robinson

For Robinson, that's the goal.

"I feel just such a sense of joy that this exists for them," she said. "I think my dad would just be really glad that I made something good come out of the grief and the pain of losing him. So, I think he's really proud."

CNN's Kathleen Toner spoke with Robinson about her work. Below is an edited version of their conversation.

CNN: You have a certain symbol that can be found throughout the center. What's its significance?

Mary Robinson: In every single support group room, we have elephants -- they're part of murals, stuffed animals, pillows. That's because in our society, grief and loss are the one thing that isn't talked about. We are afraid of people who are grieving because we don't know what to say or what to do. But here at Imagine, you talk about the elephant in the room.

CNN Hero Mary Robinson

CNN: Is there a time limit on the services you provide?

Robinson: No. That's because children re-grieve, and as they grow older, they miss their parents in a whole other way. When a 5-year-old's dad dies, he misses him in one way. When he starts Little League at 10 and sees lots of other dads around, he might get angry and start acting out. They need support at different stages of development. Some families stay for years, some only six months -- but they are always welcome to come back. There's no time frame to grieve, and it's different for everybody.

CNN: What are some other ways Imagine is helping people?

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Robinson: We are going to be opening a center in Newark in April. It's only 20 minutes away from us, but it's an urban community that's a world away in terms of resources. Children there are experiencing a lot of trauma in their lives. So, we're really thrilled about working there.

We also provide grief education in the schools. You have classrooms full of grieving students and yet nobody prepares teachers for how to deal with that. So, we go in to help the teachers and staff understand that there's things that they can do to support them.

I believe the world is driven by unresolved grief. Walk into any therapist's office, 12-step meeting or prison and you will hear stories of grief and loss. Loss is part of life, but nobody teaches us what do you do when you have all these feelings. My goal is to help kids develop coping tools and create supportive communities that can support anybody who is grieving.

Want to get involved? Check out the Imagine website and see how to help.