Leach, a parenting vlogger, documented the devastating loss on her Instagram account this week, from the day she rushed her son Crew to hospital to the unbearable aftermath of his death on Friday.

The mother explained the terrifying ordeal unfolded after she lay her youngest son down for rest at a relative’s house where the family was spending Christmas Day.

“When I went to check on him, he was not breathing. We are living a nightmare, and I’m dying inside. Please pray for my baby. This can’t be real,” she wrote.

As soon as Crew was taken to hospital, doctors stabilised the three-month-old with a ventilator while they ran tests.

“This kind of thing only happens to ‘other’ people. Not me,” the bereft mother wrote in a second post.

“Please continue to pray. Please. I don’t think I can go on without him.”

Throughout the harrowing two-day ordeal, Leach posted photos of the hospital room, while updating her followers about her son’s condition.

“Crew’s tiny earthly body is still with us, although I know he’s already dancing and playing in Heaven,” the heartbroken mum wrote alongside an Instagram update of her and her husband holding her baby.

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“We have some hard decisions to make over the next 12 hours, that no parent should ever have to make.”

“We need prayer now, more than before, specifically prayers for peace and clarity on the decisions that have to be made, and for our hearts, the pain is unbearable,” she added.

“I keep thinking that I will wake up from this nightmare, but I don’t.”

It was confirmed on Friday that Crew passed away, although no details have been released as to why he became unresponsive or his cause of death.

While doctors ran tests to prepare for organ donation, the family spent their final moments together and said their goodbyes.

“We are making hand and footprint imprints, a family handprint tree and a fingerprint charm,” Leach wrote.

“Jeff and I take turns being strong for each other, and our kids have been so strong. We are just taking things, minute by minute, hour by hour, although it feels like a daze.”

Throughout the weekend, the popular vlogger has been openly mourning, sharing each step of her grief on Instagram, and thanking her friends, family and followers for their support and prayers.

Despite her best efforts to contain her grief, Leach revealed she had found the emotional struggle in the wake of her son’s death unbearable.

“It’s all just too much. All of it,” she wrote alongside a photo she shared to Instagram on Monday.

“I know God has a plan for this, but I’m really really mad at him right now.

“I cry behind the bathroom door while Jeff holds me because in the room over everyone else gets to laugh and go on with their lives, and it makes me so angry.”

She said the worst of it was doctors continued to run tests on her baby’s body to see how his “organs are functioning” before taking them, and she has to pump breastmilk “just to pour it down the drain”.

“Hearing a baby cry. Seeing a baby his age. Shopping Nordstrom for the dress I’ll wear to my son’s funeral.

“It’s all too much. I’m sorry to vent, but this is my heart. And I need all the prayers to get through this

At this stage, the pair haven’t revealed details about Crew’s death, however, it is understood the three-month-old suffered from irreparable brain damage

“The damage to Crew’s brain is catastrophic & irreparable. We are devastated,” Jeff Leach wrote on the family’s fundraising page.

Surgery for Crew’s organ donation is planned for New Year’s Eve and it is hoped he may help save the life other children.

“We ask that you keep our family in your prayers tomorrow,” Leach wrote adding: “It will be the hardest day of our life.”