As her plane took off from a Nairobi runway toward Australia, Mami Coco Nyiramuruta thought her deliverance had come.

She, and her children, had lived through the horrors of the Rwandan genocide for a decade.

Now, they had been granted asylum Down Under and they were bound for Coffs Harbour.

But what should have been a happy moment was tinged with melancholy.

Ms Nyiramuruta had seven children with her on the flight — one was missing.

A decade earlier, the then eight-year-old Christian was making his way to a friend's house to play soccer when everything changed.

Ms Nyiramuruta in Coffs Harbour with two of her children, Adonnah (L) and Pierre Vie. ( ABC News: Meghna Bali )

Ms Nyiramuruta and her family were already living as refugees in Kinshasa, in the Democratic Republic of the Congo (DRC), when armed militants stormed their home.

"I didn't know what happened because I was cooking, fixing my house and I just saw people entered," she said.

Soldiers placed a tyre around her husband's neck, doused him in petrol and burned him alive.

Ms Nyiramuruta was gang-raped and beaten in front of her children. Their home was razed.

"I was just confused and I was crazy," she said.

"I couldn't listen to anything because of the pain … and [I'm thinking] where are my children?"

'Every day I was crying'

The root of DRC's turmoil had its origins in the 1994 Rwandan Genocide, when 800,000 were killed in a 100-day slaughter.

It was started by Rwanda's Hutu-led government and ethnic militias, before Tutsi rebels seized power and overthrew the regime.

Around 2 million Hutus, including militia responsible for the genocide, are believed to have fled into DRC, fearing a backlash.

They quickly allied themselves with the Congolese government and began attacking its sizeable population of ethnic Tutsis.

Ms Nyiramuruta and her family are native Kasaians from south-west DRC, but similarities in their facial features to Tutsis made them a target.

Immediately after the attack, she found herself in a refugee camp in Kinshasa.

Red Cross volunteers brought her children to her, but as they came closer she became hysterical.

Christian was missing.

Ms Nyiramuruta and her children during their time in a refugee camp. ( ABC News: Meghna Bali )

Aid workers began looking for him, and two years went by.

"We saw the news, we saw how people died," Ms Nyiramuruta said.

"Every day I was crying."

The family tried to live as normally as they could, sleeping in tents in the DRC and later Rwanda, surviving on canned food.

But it was a life in limbo, and a daily struggle to survive.

In 2003, after more than six years in a Rwandan refugee camp, an aid worker told Ms Nyiramuruta she was working to get them out of Africa.

Four years later, her family boarded a plane to freedom.

But she could not shake the feeling she was leaving a part of herself behind.

Being separated from one of her children has been difficult for Ms Nyiramuruta. ( ABC News: Meghna Bali )

Finding Christian

The family settled into life in Coffs Harbour, on the NSW mid-north coast.

After five years in Australia Ms Nyiramuruta's fourth child, 20-year-old Geny, began searching social media.

She was looking for Christian.

"I was the first one in my family to get Facebook," she said. "I said, I'm going to find all our family."

The first few searches did not come up with anything.

But Geny kept looking.

"[I found] this weird looking profile that didn't have a picture on it, and it had like our name … I was like: oh that's really weird," she said.

"His name was Christian."

She sent him a message. He replied.

"We thought he was a scam artist," she said.

He sent them a selfie and the similarities were indisputable.

The selfie Christian sent his sister when contacted over Facebook. ( ABC News: Meghna Bali )

He remembered his mother, and even knew Geny's childhood nickname.

She knew it was time to tell her mother.

"We cried, [and we] prayed to God," Ms Nyiramuruta said.

"I feel it all in my body, afraid and scared and happy … I said please let me see this boy."

'If this boy dies, I'll never forgive myself'

Christian is now in his late 20s, tall, has a shaved head, a long wide nose and deep-set eyes.

They're features that make living in DRC deadly for him.

After he was separated from his family, Christian was hidden by a woman who lived on the same street as them.

In their first video call, Christian told his mother he had been sleeping rough.

Unable to bear being away from her son, Ms Nyiramuruta risked her life in 2015 and went back to Africa.

Christian reunited with his mother after their 15-year separation. ( Supplied )

"I saw him, I told Christian 'I'm your mum, you believe that?'" she said.

"He told me 'I believe it'. We cried."

But Christian's dire situation took the shine off their emotional reunion.

Living in poverty meant he had no access to medication and was suffering from several health conditions.

Weak governance and the prevalence of several armed groups have subjected the people of the DRC to widespread sexual violence, murder and poverty.

Mami said the thought of leaving her son behind was so upsetting, it almost made her not return to Australia.

"At anytime they can take him away to be soldier, to go kill another and if he refuses they will kill him," she said.

"If this boy dies, I'll never forgive myself."

So far, Christian has had four visa applications rejected. ( ABC News: Meghna Bali )

For the past six years, Mami has tried four times to bring Christian to Australia on a humanitarian visa — but all four applications have been rejected.

Refugee Council of Australia chief executive Paul Power said the immigration department had received more than 74,000 applications. Only 14,825 visas were granted.

According to him, the chances of a 29-year-old male from the DRC getting in through this system was "close to zero".

"The situation looks pretty grim sadly for refugees from Congo because there isn't anything on the horizon to suggest a peace process is possible," Mr Power said.

"Essentially it's much harder for an adult male who's separated from the rest of the family for quite some time, to demonstrate that his level of dependency is greater than many of the other applications that are being put forward."

As an alternative, the Federal Government's Community Support Program allows Australians to sponsor someone in need of a humanitarian visa — such as Christian — and assist their settlement.

But there are major barriers to access, such as more than $50,000 in costs and the job-ready criteria that requires the person to speak English "well", have a recent work history, tertiary qualifications or demonstrate a capacity to find employment.

Ms Nyiramuruta described the process as "overwhelming", but said she would not give up.

"Christian is very smart he can be someone in this country, I didn't bring lazy kids," she said.

She spends her spare time picking blueberries to pay for a room for Christian to live in.

After 11 happy years in Coffs Harbour, she still hopes to, one day, have enough money to sponsor him.

But Mami's working abilities are limited. The violence she experienced in Africa left her with injuries, including a slipped disc in her spine and post-traumatic stress disorder.

For now, she's spending her days worrying if Christian will pick up her next phone call.

The Department of Home Affairs declined to comment on the matter.