Their grief is unimaginable.
Steve and Bernie Day’s daughter went from being a young, fit and healthy 29-year-old to fighting for her life in less than 24 hours.
Their beautiful Rachel had contracted sepsis, a disease that has been called "the deadliest killer you've never heard of".
She died 10 days later after an heroic battle.
Her devoted family had to watch as the deadly infection ravaged Rachel’s body causing blood clots in her vital organs, her brain, heart, lungs and kidneys and then in her arms, legs and toes.
After eight days, her family had to make the horrendous decision to amputate Rachel’s two legs and her left arm.
When she returned from surgery doctors had to break the news that her right arm had also been amputated because the infection was too severe.
Two days later, on June 7 last year, Rachel lost her fight for life.
It has been a dark and difficult year for her parents, but their determination to raise awareness of the deadly infection and need to help others is a positive force that is helping them through each day.
Since Rachel’s death, their “army” of friends and family have been working with the Sepsis Trust to fund more pathways and education resources for NHS and to start up a charity in her memory.
Mum Bernie says proudly: "The incredible support and magnitude of kindness we have been shown is all testament to Rach."
Bernie and Steve both say it is that support that has got them through the past year and made them able to get out of the bed in the morning and face each day.
The close family had spent a wonderful bank holiday weekend together as Rachel had taken a couple of days off from her job at Llanishen Leisure Centre before everything changed.
They had visited Cardiff Bay and Rachel had spent time with her young nephew Morgan and her parents.
But in the early hours of Monday morning, Rachel felt so ill she visited A&E and told staff there she felt like she was dying.
Bernie says: “She had all the classic signs of sepsis but was sent home with paracetamol and told to rest.
“Rachel was sent home to die, she went into a septic shock state, her blood pressure dropped to a dangerously low level and when I found her later that afternoon she was screaming in pain.
“She spent the next 10 days of her life on ICU at the Heath fighting for her life and it was extremely cruel to watch as sepsis ravage Rachel’s body and her beautiful face.
“When they told us they would have to amputate her arm and both legs we thought that at least with one arm she would be able to operate a wheelchair or hold her nephew, but then the doctors told us they had had to amputate her left arm too.
“She was able to communicate with us at times through blinking and she put up an heroic fight, but in the end it was too much.”
The shock for the family and friends was immeasurable. They had never even heard of sepsis before it cruelly took their daughter and friend.
In the UK, it is responsible for 44,000 deaths every year, which is more than bowel, breast and prostate cancer combined.
Despite this a recent survey found that 44% of people in the UK have never heard of the infection and have little idea that it is a life-threatening emergency.
The Day family, supported by many friends, are now on a mission to increase that awareness in the hope of saving lives.
Dad Steve points out that treatment for sepsis if it is caught early enough is intravenous antibiotics that only cost between £15 and £20 per person.
An event in Rachel’s memory just weeks after her death last year raised more than £4,000 which has paid for the ‘Sepsis 6 Pathway’ scheme at Wales’ largest hospital.
It means that anyone who goes into the Heath hospital in Cardiff with a fever or signs of an infection will be checked for ‘red flag’ symptoms of sepsis.
Bernie explains: “If it is flagged the Sepsis 6 car bundle is triggered within an hour of diagnosis which involves three simple tests and three simple treatments. Rachel is now saving lives and it makes it a bit easier.
"We know of people who have heard Rachel's story and who have gone to the doctor and sepsis has been caught in time.”
One of Rachel’s great loves was dogs and to supplement her income Rachel worked for Friends For Pets Cardiff.
Colleagues Catherine Clarke and Sally Kirkpatrick approached Bernie and Steve at the celebration of her life to suggest the fundraising day and it was such success they are holding it again this year at the Rhiwbina Recreation Club in Cardiff on July 14.
The plan is to create a charity in Rachel’s name to help other victims of sepsis and to raise the all important awareness.