"If it wasn't for this group, I don't know where I'd be," says Brad Watson as he sits in the visitor's room of children's hospice Ty Hafan.
The 40-year-old's son Archie died aged two, in 2013, of a rare genetic condition.
Mr Watson was grateful he could count on dads in a 100-strong support group during the traumatic time.
As well as forming strong friendships, they managed to tackle five mountains in just two days.
"Archie was like any other healthy baby boy. I called him the next number nine for Wales at the time," recalls West Ham fan Brad.
"Then, at about nine months old, we realised that he wasn't hitting a number of milestones and didn't seem to be learning quickly...
"He was having seizures, and I thought it was epilepsy."
Following countless tests and scans, doctors broke the news that Archie had an incurable condition.
He was diagnosed with Tay-Sachs Disease.
Brad said: "He was then referred to Ty Hafan - something which I felt uneasy about, because I thought a hospice was going to be a grey dull place where he'd be sent to die. Little did I know how wrong I was."
Built in 1999, Ty Hafan Hospice in Sully is on the coast between Penarth Pier and Barry Island - and is surrounded by green fields and trees.
Looking like a holiday complex from the outside, inside it is full of bright colours and the sound of children's laughter can be heard along its corridors.
Father-of-three Paul Fears, of Pontypridd, remembers the first time he pulled up its quiet driveway.
"I saw a child who was attached to drip with a sponge in his hand with his face beaming, as he was taking part in a huge water fight," he smiled.
"That changed my perception immediately."
The 52-year-old's son Greg was diagnosed with pulmonary hypertension aged two, and was not expected to live for very long.
"Coming to terms with the situation was incredibly hard," recalled professional photographer Paul. "I don't know whether it was being a man, but talking about it wasn't easy.
"Male friends of mine wanted to help - but I think it was hard for them to understand.
"Sometimes you would talk about the reality of the situation, and I don't think they knew what to say. Or they'd feel awkward if I opened up and talked about how I felt.
"I think women tend to speak more about their emotions, but men don't sometimes."
Greg, now 27, was transferred to adult care after turning 18.
But his father has never forgotten the good work Ty Hafan did - and is part of the dads' "wolfpack".
The group comprises of fathers whose children who are either cared for at Ty Hafan or have been in the past - and aims to provide practical as well as emotional support.
Organiser and support worker Gareth Jenkins, 39, says there is much more to the group than meets the eye.
"It's not just about talking about feelings - it's about giving practical support and first-hand advice on a range of things. Say for example, if someone wants to find out about getting something like a specially-adapted wheelchair, they can ask one of the other dads rather than trawl through the internet for ages.
"It's also about having fun and forming friendships, with others who know what it's like to go through their situation.
"It gives them the chance for some respite and to be themselves again.
"We've done everything from paint-balling, to going to watch the rugby and football."
And earlier this Summer, 16 of the group set themselves almost an impossible task: tackling Ben Nevis, Scafell Pike and Snowdon before going up Cader Idris and then Pen y Fan - all in two days.
Brad said: "Someone suggested we did the Three Peaks challenge, but then as a joke Gareth said we should do five peaks...
"Amazingly, lots of us were up for it, and gave it a go."
As well as strengthening their friendships even further, the group also managed to raise £30,000.
However, for Paul, the strong message that the group has sent out has been one of the most valuable things for him.
"I remember hearing from one dad, whose son had a life-limiting condition, that seeing our photos of the trek on Facebook really struck a chord with him.
"He said that seeing dads like him laughing and joking - gave him hope that he would one day be able to do the same again.
"There's been a lot in the news recently about men's mental health and how we need to open up more. And I think attitudes are changing, which is good.
"Every Ty Hafan dad has his own mountain to climb when caring for a child with a life-limiting condition - hopefully things like our five peaks challenge will support and inspire others."