Loren and Daniel O'Keeffe always had the kind of close sibling relationship parents dream of for their children.
"There's two-and-a-half years between us and he was the baby boy – I was besotted with him," Loren, 36, tells Woman's Day.
"We had a really similar sense of humour – we were always looking across the dining table and rolling our eyes at the same things Mum and Dad were saying. He was my little sidekick."
The pair remained close as they moved into adulthood and although Loren admits she remained protective of her brother, she was "really proud" of the young man Dan was becoming.
But at 24, Dan – who ran a successful Brazilian jujitsu academy in Melbourne – was struggling with his mental health. Suffering from depression and anxiety, he turned to Loren for support.
"He became increasingly reliant on me to help and I was privileged to do so. I would have done anything for him – he always knew that."
When Dan went missing on July 15, 2011, Loren, then 26, couldn't comprehend how her brother could have suddenly disappeared, seemingly without a trace.
"We were always very close," Loren says, "Which is partly why I was so stunned when he vanished. I didn't feel like I had any hint."
When it became clear the police didn't have the resources to help find Dan, and with the O'Keeffe family increasingly concerned, they began their own search campaign.
They rang hospitals and crisis accommodations, organised local searches and took to social media to spread the word.
Every lead was considered, every sighting looked into, and even though ultimately they proved fruitless, Loren felt she had no choice but to continue.
"When you're that desperate, there's no alternative," she says.
"Hope is typically the only thing you've really got while your loved one is missing."
Loren gave up her job in communications to head up the Dan Come Home campaign to ensure images of her smiling, handsome brother flooded social media, news outlets and noticeboards across Australia.
Along with the rest of the O'Keeffe family – mum Lori, dad Des and Loren's older sisters Vicki and Kate – Loren searched tirelessly to find her brother and remind the public to keep looking.
She kept two mobile phones – one personal and one for the search hotline – switched on and by her side day and night.
But as the months, then years, ticked by without any sign of Dan, Loren's personal and social life, friendships, work and even her health were sidelined.
"I remember Mum saying she didn't want to lose another child, but I couldn't not do what I was doing," she says.
"I was so concerned about my baby brother, and I was going to do everything in my power to try and find him."
In 2016, nearly five years after he went missing, Dan's remains were found in a previously unknown and inaccessible underground cavity below the family property near Geelong.
Police confirmed there were no suspicious circumstances surrounding his death – he had taken his own life.
For Loren, knowing for certain that Dan was gone was a relief of sorts.
"When you finally do get that confirmation – if you're fortunate enough to – it's brutal, but for me at least, it's definitely more bearable to live with knowledge that he's no longer alive than not knowing where he is."
But amid the relief, Loren still has moments of wishing she was still looking for Dan, who would have turned 34 this year.
"Some days I wish I was back in that time when I did have that hope. That I could allow myself to imagine that he might just, you know, rock up for Christmas that year.
"But I think day to day there's relief in knowing that I don't have to keep searching," says Loren.
In 2013, Melbourne-based Loren founded the Missing Persons Advocacy Network (MPAN) to provide practical support for friends and families of missing people.
It's a role she feels lucky to have, because it means she has a reason to talk about and celebrate Dan every day as part of her work.
"Dan is constantly living in my imagination, and in my heart," she says. "I feel lucky to be able to do something that really does keep him close to me all the time."