A mum told her granddad "I love you" in her final conversation with him before she was killed in a fire which also claimed the lives of her husband and four-year-old daughter.
Damien Parr, who was the last family member to speak to mother-of-four Kaylie Rudge before her death, said he was "absolutely numb and devastated" by the tragedy.
Kaylie, described as a "beautiful, sweet young lady", died alongside husband Daniel and daughter Lillie-Rose after a blaze started in the front room of their home in Exeter on Saturday.
Two boys, aged four and nine, and a seven-year-old girl, are being treated in Bristol Royal Hospital for Children.
Police confirmed the four-year-old boy is Lillie-Rose's twin brother, Devon Live reports.
Kaylie's heartbroken mother Vanessa Parr is by the children's side at the hospital.
A fundraising appeal has been launched to raise vital money to help care for the youngsters, as well as to help cover the cost of funeral arrangements.
Kaylie's granddad Damien Parr was the last family member to speak to her before she died.
He said: "She rang me the night before this tragedy and said, 'dad, I'm just checking everything is all right with you and mum, and can you tell me if there is anything I can do for you?'.
"She called me dad because I brought her up for a few years.
"I told her I was fine and the last words she said to me were, 'dad I love you, I will ring you in two days' time and have a chat again'.
"We are absolutely numb and devastated by all that has happened.
"We can't get our heads around it to be honest. Every day is a struggle and we don't know whether we are coming or going at the moment."
An investigation found that the blaze started accidentally in the lounge.
Damien said: "It started in the front room and was caused by an accidental naked flame.
"We would like to thank Devon and Somerset Fire and Rescue Service, the ambulance personnel and police for all their efforts to get the family out. We can't thank them enough for what they did."
So far more than £4,000 has been raised.
Another fundraiser has also been set up for Daniel to help the family cover costs for funerals, travel, childcare and for the other children in the present and the future has raised more than £32,000.
The family say they have been overwhelmed by the support their fundraiser has received which will help care for the youngsters, as well as to help cover the cost of funeral arrangements.
Funds left over following the funeral will be donated to The Grand Appeal the Bristol Children's Hospital Charity.
Damien said: "We are surprised and grateful, very much so, for all the support the fundraiser for Kaylie's family and the hospital has received so far.
"Kaylie was a beautiful, sweet young lady who would do anything for everybody. She was a fantastic mum and was the type of person who would give you her last pound.
"If she was walking up the high street and saw a little child and her children were eating sweets, she would go in a shop to buy that child sweets too."
