A few days before he died, Charlie Stowe's dad gave him a long hug.
"He didn't let go for like five minutes. The hug was his way of saying goodbye," Charlie, 19, said
Charlie is hiking the 300-kilometre Great North Walk from Sydney to Newcastle over 12 days in memory of his father Richard Stowe, who died at age 63.
He was diagnosed with young-onset frontotemporal dementia (FTD) a decade earlier.
"I never really got to know my dad that well," said Charlie, who was eight at the time of the diagnosis.
"I watched the person who raised me slowly disappear."
As part of his hike, Charlie is also walking for families living with the uncertainty of FTD.
"Losing someone you love while they are still physically here is a kind of grief no family should endure," he said.
Richard died two years ago, but Charlie said "we lost him eight or nine years ago".
Charlie, of Balgowlah, is mostly doing the walk solo, with friends and family - including his mum and sister - joining him in parts along the way.
"The section from Berowra to Brooklyn was one I used to do with Dad a lot when I was a child, so that brought up some memories," he said.
"It's nice memories and realising he'll be so proud of what I'm doing.
"I feel like he's looking out for me with the good weather. In lots of different ways, everything seems to work out very well and I always say 'thanks Dad'."
As he approached Newcastle, Charlie recalled that the family would take holidays in the Hunter Valley before his dad declined.
"FTD changes a person's behaviour, personality and eventually deteriorates the very functions that make us human," he said.
"Seeing someone you love fade slowly is a kind of grief that's hard to put into words."
Charlie struggled to cope with the loss of his dad for a long time.
"I started hanging around the wrong crowd and went off the rails a bit. I was only connecting to people with trauma," he said.
"Eventually, I found my way back through the outdoors, a place that had always connected my dad and me."
Since then, he has travelled and spent more time in nature.
"It's shown me not only how beautiful the world is, but also the kindness of people and the importance of gratitude and perspective," he said.
"It reminded me that even after immense loss, there is still so much to be thankful for."
Charlie is using the hike to raise money for Frontier, a research group at the University of Sydney's Brain and Mind Centre.
It is the largest clinical research group in Australia dedicated to investigating FTD.
Charlie said Frontier "helped significantly with my dad's disease".
"He was misdiagnosed with depression for two years and treated for that. Frontier found out he had frontotemporal dementia. They also gave us referrals and support," he said.
David Foxe, clinical neuropsychologist and researcher with the Frontier Research Group, said "we're enormously grateful to Charlie for his remarkable efforts".
"Historically, FTD has been under-recognised, under-researched and under-diagnosed globally," Dr Foxe said.
He said new discoveries were "transforming our understanding of the condition".
"Our research spans behaviour, cognition, social functioning, speech and language, clinical management and many other aspects of FTD and dementia more broadly," he said.
He said the group worked closely with carers and families to "inform diagnosis and better understand changes in cognition and daily functioning".
