Jenny Bowles also spoke of how the community has been “broken” by the suspected triple murder and attempted suicide near Maguiresbridge.
Vanessa Whyte (45) died along with her children James (14) and 13-year-old Sara.
Last night hundreds gathered for a vigil in memory of the three.
People wrapped their arms around each other at the event, which was organised by a community group and held at the local primary school that James and Sara once attended.
First Minister Michelle O’Neill was among the crowd.
Childminder Jenny Bowles at Friday night’s vigil.
Also present was Ms Bowles, who was childminder for James and Sara for eight years from when they were about three months old each.
She said the tragedy has left the community shattered.
“Our family — we’re just devastated,” she told the Belfast Telegraph.
“James and Sara were just like our own children. We treated them like our own family and they both were very fond of my own two boys, Jordan and Adam.
“James looked to Jordan and Adam as his brothers. They were his role models.
“Vanessa was such a lovely person, very hard-working and a very strong person.
“To describe her, she was just so lovely. James and Sara were great. They loved the outdoors.
“James loved machinery, especially the harvester at this time of the year. Sara loved the animals on the farm.
“They were big into their sports, and I know when we had James at our house he loved the football.”
The shooting happened at a house near Maguiresbridge on Wednesday morning.
Vanessa and Sara were pronounced dead at the scene. James died a short time later in the South West Acute Hospital from the injuries he sustained.
A man remains in a critical condition at the Royal Victoria Hospital in Belfast.
Describing her reaction to the tragedy, Ms Bowles added: “I just went into complete shock. I couldn’t even find the words to tell my husband. We are just heartbroken.
“Sara and James were just part of our family. They loved outdoors, and they would have rather been out helping and working, rather than sitting in, playing with toys. James absolutely loved getting out to help my husband in the workshop and making wee things out there or tidying up.
“They were just an exceptional family. Vanessa was just exceptional in every way, and so were the children.
“To describe the community, I would say… broken.
“James had really wanted to get to Enniskillen Royal Grammar School too, because Jordan and Adam had gone there, and he achieved that.”
Vanessa Whyte with her daughter Sara and son James who died following a shooting in Co Fermanagh
She also told how James had become an Arsenal supporter, because her own two sons were.
Jenny added that the local community has been “amazing” in the unity they’ve shown and praised the fact all denominations have been able to “come together under some tragic circumstances”.
Multiple clergy led the large crowds in prayer at the vigil, including Rev Rodney Beacom, a local Presbyterian minister; Passionist priest Brian D’Arcy, and the Church of Ireland’s Rev Lindsey Farrell.
A two-minute silence was held, with a poem read by the vice chairperson of Maguiresbridge Development Association, Sonya Smith.
She recited: “How do we go on? After the unthinkable happens, how can we carry the burden of knowing? The world can be cruel and dangerous, the future so unpredictable.”
Also in attendance at the vigil was the local MP Pat Cullen, former MP Michelle Gildernew, and MLAs Aine Murphy, Jemma Dolan and Deborah Erskine.
Agriculture Minister Andrew Muir was also there. Ms Whyte had worked for his department, and had recently been promoted to the most senior government vet within Co Fermanagh.
Jenny Bowles cared for Sara and James since they were very young.
Watch: DUP Leader Gavin Robinson pays respects to mother and children killed in Fermanagh shooting
She had also formerly been part of the Maguiresbridge Running Club.
Yesterday evening, some of its members remembered her as being “full of life” and “very determined”.
“Just for someone so ordinary, so hardworking, the soul of the community and of so many different clubs and in a cross-community capacity — she didn’t deserve that,” one member said.
Another said that the running club’s route often takes them past the family’s house, noting that “it will never be the same” each time they pass it now.
Many people stayed after the vigil for hours, queuing to sign the book of condolences that has been set up for members of the public to pay their respects to Ms Whyte and her children.
People have attended a vigil for Vanessa Whyte, 45, and her children, James, 14, and Sara, 13 (Liam McBurney/PA)
Members of all ages from St Mary’s Maguiresbridge Gaelic football club, and Lisbellaw Hurling Club, of which all three shooting victims were “active and beloved” members, walked together to the vigil from the local GAA pitch.
St Mary’s described Sara as “a joy to be around and always had a smile on her face”.
The club said that James, who was captain of the under-14 team this year, “was the heartbeat of our team and he had the confidence to be vocal and show leadership to younger team members”.
They said that Ms Whyte “had a passion for our games that encompassed everything good about the GAA showing dedication, sportsmanship, and camaraderie, and it was clear to see how Vanessa instilled these same values in her children”.
James and Sara both attended Enniskillen Royal, and the school announced that it will be open all of next week for any of its students or other young people that need help and support.