Little Harri Stickler's short life has already been an incredibly hard fight.
Born eight weeks premature, he was just six months old when he was diagnosed with a very rare and aggressive form of cancer and given only a 20-30% chance of survival by his doctors.
Since then his battle against acute lymphoblastic leukaemia has tested both him and his devastated family to the utmost limit.
Read more: The little girl with an ultra-rare condition that affects just 100 people worldwide
And now his parents claim they need to raise as much as £1m to fly him overseas for pioneering treatment that could very well be his last hope.
"It's been a rough ride for Harri ever since he came into this world," said his mum Bethan Morgan, 29, from Aberdare, who recently launched an online GoFundMe page in a desperate attempt to achieve the funds they need to save him.
Without it she admitted her son will barely make it past his fourth birthday in June.
"Doctors have told me that if Harri doesn't get treatment by summer then by summer there'll be no Harri," she said, adding that, while that very thought breaks her heart, she can't allow herself to cry.
"Somewhere there's a clock counting down and from the moment I got told that I went straight into fight mode.
"I decided to try to find the money needed myself, and, in the short time the appeal's been online, more than £35k has been raised.
"That blows my mind - everyone's been so fantastic, so supportive."
Bethan explained that Harri's ordeal began back in December 2018 when she noticed his left eye had turned bloodshot.
She took him to Prince Charles Hospital in Merthyr Tydfil where tests confirmed the nightmare cancer diagnosis, along with the shattering news that the odds of survival were stacked against the plucky tot, leaving him requiring urgent treatment in intensive care.
However, a bone marrow transplant at Bristol Children's Hospital in April 2019 saw Harri's luck change.
Having spent his first birthday in hospital, he was finally allowed to return home to be with his big brother Logan the following month.
Yet the family's relief proved short-lived - Bethan spotted a lump in the middle of Harri's forehead during a family holiday that summer, along with a tiny red dot on his leg, and instantly realised the cancer had returned.
The only hope was for their little one to undergo pioneering new treatment called Car T Cell therapy, a complex type of immunotherapy where specialist doctors collect infection-fighting cells from the patient, modify them and plant them back into the body to fight disease.
Harri spent six weeks in isolation at Great Ormond Street Hospital in London in late 2019 before finally getting the green light.
What followed was a year and a half illness free, but, sadly, Harri relapsed last summer - since which time various different attempts to find a solution have come to nothing.
"Last week we finally got told there are no more options available for Harri in this country," said Bethan.
"Our only course of action now is to fly him overseas, to either Singapore or the USA, where there are different medications and techniques available."
But the price tag to get him over there for treatment has been estimated at somewhere between £700k and £1m.
"We're looking at possibly more Car T Cell therapy and another bone marrow transplant - at the moment they're the only avenues we're aware of."
"That said, our consultant in Cardiff is bending over backwards to try and find a way to help Harri, whether it's here or abroad, and we'll continue with the chemo in the meantime provided he stays well."
Former restaurant worker Bethan revealed that she and her partner Rhys, an asbestos remover, haven't been able to go to work for more than two years due to the whole family having to isolate both before and throughout the pandemic.
"Harri has no immune system so it's a huge risk for us to go anywhere unless it's strictly necessary.
"Logan's not even been able to go to school because we don't want him picking up a bug from the other kids and passing it on."
As a result, life for the Sticklers has been like Groundhog Day, endlessly repeating itself.
"We've been back and forth to the University Hospital of Wales in Cardiff, day in day out, since October last year, it's exhausting," said Bethan.
"Luckily the one person who's been the least affected is Harri himself.
"When we get there he goes straight to the play room and grabs all his favourite toys. He's treated like a king - the staff there spoil him rotten."
And, while that's at least some comfort for Bethan, she's only too aware that this is her little one's last chance.
"As much as I know that's true, I still can't say the words. To do so would feel like a betrayal," she said.
"But, as time goes on and Harri gets worse, I'm sure there'll come a point where reality will hit me hard.
"Until then though I've no time to sit around feeling sorry for myself.
"We need that money to save our son and I'll fight as hard as I can and do whatever it takes to get it."
For more details about Harri's GoFundMe page, click here.
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