"I'll just go to heaven and play until you get there. You'll come, right mummy?"

Ruth says his passing was an "agony like no other".

"His last few days shined with how amazing my son is. How beautiful he is. How he was made of nothing but pure love," she said.

On February 1st, only four weeks after Nolan underwent open chest surgery, Ruth discovered her son had large tumours that were compressing his bronchial tubes and heart.

Hospital staff tried to make the little boy as comfortable as possible. He hadn't eaten or drunk for days and was "continually vomiting".

Doctors told Ruth the cancer was now untreatable and her four-year-old would deteriorate rapidly.

"After a while, I composed myself and went into Nolan's room," said Ruth.

"He was sitting in 'Mummy's Red Chair' watching YouTube on his tablet. I sat down with him and put my head up against his and had the following conversation:

Me: Poot, it hurts to breathe doesn't it?
Nolan: Weeeelll.... yeah.
Me: You're in a lot of pain aren't you baby?
Nolan: (looking down) Yeah.
Me: Poot, this cancer stuff sucks. You don't have to fight anymore.
Nolan: (Pure Happiness) I DONT??!! But I will for you Mummy!!
Me: No Poot!! Is that what you have been doing?? Fighting for Mummy??
Nolan: Well DUH!!
Me: Nolan Ray, what is Mummy's job?
Nolan: To keep me SAFE! (With a big grin)
Me: Honey ... I can't do that anymore here. The only way I can keep you safe is in Heaven. (My heart shattering)
Nolan: Sooooo I'll just go to Heaven and play until you get there! You'll come right?
Me: Absolutely!! You can't get rid of Mummy that easy!!
Nolan: Thank you Mummy!!! I'll go play with Hunter and Brylee and Henry!!," said Ruth.

Nolan slept for the following day and most of the days after.

"When he woke up we had the van packed and I had his shoes in my hand to take him home for the evening," said Ruth.

"We just wanted ONE more night together. But as he woke, he gently put his hand on mine and said 'Mummy, it's ok. Let's just stay here ok?' My four-year-old hero was trying to make sure things were easy for me."

During the next 36 hours, the pair made funeral plans together, Nolan wrote a will.

"About 9:00pm we were watching YouTube in bed (Peppa Pig actually) and I asked Nolan if I could get in the shower, as I was not allowed to leave him and Mummy had to be touching him at all times," said Ruth.

"He said 'Ummmm ok Mummy. Have Uncle Chris come sit with me and I'll turn this way so I can see you'. I stood at the bathroom door, turned to him and said 'Keep looking right here Poot, I'll be out in two seconds'. He smiled at me. I shut the bathroom door. They said the moment the bathroom door clicked he shut his eyes and went into a deep sleep, beginning the end of life passing."

"When I opened the bathroom door, his Team was surrounding his bed and every head turned and looked at me with tears in their eyes. They said 'Ruth, he's in a deep sleep. He can't feel anything'."

Ruth said she then ran and jumped into bed with her son and a "miracle" happened.

"My angel took a breath, opened his eyes, smiled at me and said 'I love you Mummy', turned his head towards me and at 11:54 pm Sgt. Rollin Nolan Scully passed away as I was singing 'You are My Sunshine' in his ear."

"He woke up out of a coma to say he loved me with a smile on his face," she said.

Ruth says her son died a hero.

"He was a warrior who died with dignity and love to the last second."

The Maryland mother has called for better funding, research and treatment options for Nolan's rare cancer - Rhabdomyosarcoma.

"My hope is that this nightmare makes a difference in someone's life or in childhood cancer research and treatment options," Ruth told Mamamia.

"Now I'm the one terrified to shower," she said.

"With nothing but an empty shower rug now where once a beautiful perfect little boy laid waiting for his Mummy."

Podcast:Everyone needs a friend like Tracy Bevan.