"My mum is going to die in the next few months, she's a mess, every day I go home and I cry."
Candidly speaking to the Huffington Post UK, film-maker Lee Pearse described how a "beautiful, caring, person that would do anything for anybody," has become a shell of a human being.
Dementia has long been a global issue, but ahead of a London summit, experts have acknowledged that progress on research and treatment for the disease has been "achingly slow".
It's a struggle Lee has suffered with personally. The realisation that his mother was ill was a gradual one. Ten years ago he began to notice she was withdrawing from family life. Then Valerie, who had always been family focused, became increasingly uninvolved and emotionless.
As her behaviour became increasingly erratic, her family's confusion and frustration correspondingly grew.
The powerful video, above, showcases the battle Lee and his brother, Andrew, have had with the devastating disease.
It's an issue we face in the UK, Lee said, that people are unable to recognise the symptoms of dementia, that there is a "fear" surrounding the disease.
"Doctors fobbed us off for two years," he said. "They dismissed mum's illness as depression, the frustration got to the point that I felt like I wanted to kill these people.
"Everybody is absolutely shit-scared about dementia. They are scared by a lack of knowledge, scared because we don't understand it, but they are mainly scared because the person you love becomes someone else. Everything you may have known about that person has the potential to be completely changed."
"I was scared, I still am. People quite simply don't know how to deal with this."
A consequence of this lack of knowledge, Lee says, is that carers, like him and his brother are left with an overwhelming feeling of guilt.
"We're so wrapped in guilt - I know we couldn't have stopped mum getting dementia, but we're haunted by the fact we could have recognised it earlier.
"She's not spoken properly for five years, all her teeth have rotted in her head, she's rigid like a board. But we still see glimpses of our mum, just in her eyes. All we think everyday is 'is she in pain? Is she in pain?' And she can't tell us that."
"She just stares at me, straight into my eyes. I have to clean my mum, I shave her legs, brush her teeth and comb her hair everyday. But the fear never goes away."
"It's so hard to describe, but it's like an alien invasion, it's like the person you love turns into a zombie."
It's a difficult question to ask, but does Lee feel any relief in the knowledge that his mother will soon pass away?
"We're aware of the reality but it doesn't stop the pain," he said. "I dread the phone going everyday, that final phone call that she has died and I wasn't there."
"When someone you love gets dementia, it is like you get it too. You might not have it neurologically, but with regards to everyday life you are thrown into this disease and it'll have the same crippling effect. It has nearly killed me."
Lee's comments came as David Cameron announced Thursday that dementia is "one of the greatest enemies of humanity" in a call for action to fight the disease.
A "bold, global push" is urgently needed to find effective treatments the PM said, as it was announced 40 million people worldwide now have the disease.
And the number is set to double every 20 years, unless scientists find some way of slowing or preventing the slow decline in brain function.
Lee, who is a Champion of Alzheimer’s Research UK, is trying to add an emotional element to a baffling and heartbreaking issue that, he said, is too dominated by "crazy terminology that nobody understands."
"Ultimately people need to know that people get ill," he said. "The disease needs to stop being looked at as something that "simply happens when you're older."