Now Julie, 46, has been named Tesco Compassionate Mum of the Year and will receive an award next Sunday at a ceremony in London with her entire family.
"It's lovely to be rewarded for what I've done for the kids, and the weekend will be a real treat because I don't get much time for pampering any more," she says.
"To me, I did what anybody would do in my place. I've gained so much from it because the children are wonderful. I love them, and as far as I'm concerned they're mine.
I miss Caroline so much. I can hear her voice crystal-clear in my memory. But she lives on through them, so I'll always have a part of her.
Julie has adopted Michael, 12, James, 10, Kieran, 11, Emma, eight, and Chantelle, six, after both their parents died within six months of each other two years ago. Their eldest brother, Caroline's oldest son Tim, 17, visits regularly.
Overnight Julie became a mother of eight. She somehow juggles working 40 hours a week as an RAF administrator with looking after her extended family.
Many women would have been daunted by the decision to take in five grief-stricken children when coping with grief for their lifelong best friend. But for Julie it was a simple decision.
I never wonder for a second if I did the right thing. There was never any question. What kind of a friend would I have been if I'd turned my back on Caroline's children? I couldn't have lived with myself.
Julie and Caroline's friendship began at their first day at secondary school in Grantham, Lincolnshire in 1979. When Julie married in 1988, Caroline was her bridesmaid. Julie and her RAF husband – who divorced seven years ago – moved around the country but often invited Caroline to visit.
In 1998, Julie was maid of honour when Caroline married David Atkin, a caretaker with whom she already had two children. She went on to have three more, with Julie as godmother.
"They were a devoted couple," says Julie. "Caroline lived for him and the children."
At the start of 2009, Caroline began to suffer headaches. She tripped and fell on more than one occasion, so Julie encouraged her to visit the doctor. Then one morning Julie received a shocking call from David saying Caroline had been suffering seizures and had been admitted to hospital.
"They operated straight away to remove part of a brain tumour and, when I got there, she was drifting in and out of consciousness. I knew it was very serious. Dave was distraught. I told him I'd do everything I possibly could to support them," she says.
Over the following months, with Julie by her side, Caroline received chemotherapy, but it became clear she would not survive.
Then, suddenly, just before Christmas 2009, David collapsed, having suffered a massive stroke which Julie believes was stress-related. On January 8, 2010, he died.
"Caroline called me and said, 'It's my husband, he's died,' which was an odd thing to say. She was at home and on very strong medication, so I don't think she quite understood what had happened. I was absolutely stunned."
At Easter, Julie went to Caroline's house in Lincoln with eggs for the children and, as the children played outside, Caroline broke down. Julie says: "She couldn't bear the thought of leaving the kids, so she never discussed dying, but that day she said, 'I'm so scared for my life.'
"She said, 'Will you look after them for me?' I said, 'Yes. Let's call that Plan B.'" I told her she would be fine and she said, 'What about the children?' I said they'd be fine too. She said, 'Will you look after them for me?' I said, 'Yes. Let's call that Plan B.'
"I wanted her to have that hope because I knew that was how she was coping. I wasn't surprised she had asked, and I didn't even have to think about it. I knew she would do the same for me.'
Caroline had no other relatives aside from her elderly mother, Irene, who gave Julie her blessing that afternoon. Caroline and Julie visited a solicitor to make arrangements for Julie to be the children's legal guardian in the event of Caroline's death.
The following month, Julie invited the whole family to stay at her house in Huntingdon, Cambridgeshire, for a week.
While Caroline rested, Julie organised picnics and barbecues and a birthday party for Keiran, who had just turned 10.
During the week, Julie noticed that Caroline had started to direct her children's requests for drinks or to play outside to her. "I think she was handing me her children," says Julie. "She seemed at peace with it. I'm so glad we had that week, so she could see life would be OK for the kids.
Caroline died the following Monday, on June 7 2010. A family friend was looking after her children at home. Julie arrived at the hospital 10 minutes after her friend died. "She would have laughed and said, 'You're always late,' " she says.
The children had no idea that their mummy was dying, so I had to tell them she was gone and that she was with the angels in heaven.
"I said, 'Who wants to come home with me?' and they all said, 'I do.' "
During the first few days, Julie's mother helped to take care of the children while she organised Caroline's funeral and underwent checks by social services.
When she got the children home, Julie was faced with immediate practical difficulties. With two double and two single bedrooms, fitting everyone in was a struggle.
"I moved the table out of the living room and set up camp beds for the girls. Then someone arrived with a tent. It was summer, so I let the boys sleep in it in the garden," she says.
"Adam, my eldest, went to university a bit early so we could use his room. I put bunk beds and a single bed in there for the boys, and the girls have bunks in the dining room. Adam has to sleep on the sofa when he comes home for the holidays."
The maturity with which Julie's three children, Adam, now 21, Peter, 19, and Christian, 14, have coped with the upheaval is a credit to them and her. When she told them Caroline was dying, they needed no prompting to suggest the children come to live with them.
"They've been brilliant," says Julie. 'Christian has moaned every now and then, saying, 'The little weasels have been in my room,' but they've been very tolerant. They're older but I make sure nothing's been taken from them apart from space."
Although Caroline's children felt comfortable with Julie from the start, the loss of their mother had inevitable consequences.
"Michael was being sick a lot for the first three months, I think because of the shock. Emma had temper tantrums. The younger boys had trouble sleeping and Chantelle was very clingy.
"I noticed that every reading book they brought home from school seemed to be about Mummy and Daddy. There were a lot of difficult moments. But gradually, with a lot of love and care, they settled down.
"I try to keep things simple. I say to them, 'This is a calm house. We've only got each other so we have to get along.' I insist on good manners and respect.
"The girls are in bed by seven and the boys by eight. We read together and they aren't allowed to watch TV during the week. At first they were quite behind at school, but they've done really well. They work hard to make me proud."
Julie talks about Caroline and David with the children often to ensure they will never be forgotten. She marks Caroline's birthday by taking them all on a trip to the seaside and, during the holidays, the children visit their grandmother Irene.
"I've made memory boxes for all of them with the few bits and pieces I salvaged from Caroline's house – a few pictures and pieces of jewellery. I'm also filling them with new, happy memories, like pictures from our trips together, trying to make their lives as normal as possible."
She receives child benefit, but nothing else, and works 40 hours a week to make ends meet, with the children going to an after-school club. She says she has been advised to move into a council house and claim benefits, but has refused.
"A lot of days I'm exhausted because I work a full day and then I come home and have to start again with cooking, cleaning and washing. I have to keep a diary to remember everything all the kids are supposed to be doing every day.
"Family and friends help out with childcare and shopping, and bring round clothes for the children, and people at work have been brilliant."
What an amazing woman!