Kaitlin Burge's son Beckett was diagnosed on April 25, 2018 with Acute Lymphoblastic Leukemia.
Burge created the Beckett Strong Facebook page to provide updates on his journey.
In her most recent post last week, Burge opened up more, not just talking about the financial and medical struggles of cancer, but showing the toll it takes on young siblings as well.
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The post has two photos, including one of her daughter, who has her hand gently placed on Beckett.
"My two kids, 15 months apart, went from playing in school and at home together to sitting in a cold hospital room together. My then 4-year-old watched her brother go from an ambulance to the ICU," Burge began.
"She watched a dozen doctors throw a mask over his face, poke and prod him with needles, pump a dozen medications through his body, all while he laid there helplessly. She wasn't sure what was happening. All she knew was that something was wrong with her brother, her best friend," she continued.
A little over a month after Beckett was released from the hospital, Burge says her daughter struggled to understand how her brother went from being lively, energetic and outgoing to "now a quiet, sick, and very sleepy little boy. He never wanted to play."
"She didn't understand how he was able to walk before this, but now he can't even stand unassisted. She didn't understand the different therapies he had to attend to gain his strength back. To her, it was something special he got to do that she didn't. Why couldn't they go to their favorite trampoline park anymore? Why couldn't they go to the splash pads they previously went to? Why didn't he have to go back to school, but she did?" Burge said in the post.
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She candidly explained why Beckett's sister went to the hospital with them, saying that "children need support and togetherness, and should not be kept at a distance from the person who is ill."
She said that her daughter, who is now 5 years old, has "spent a fair amount of time, by his side in the bathroom, while he got sick. She stuck by him. She supported him and she took care of him, regardless of the situation. To this day, they are closer. She always takes care of him."
Beckett has just turned 4 years old.
Burge ended the post on a poignant note.
"Vomiting between play sessions. Waking up to throw up. Standing by her brother's side and rubbing his back while he gets sick. Going from 30 lbs to 20 lbs. This is childhood cancer. Take it or leave it," she wrote.
As of this story, her post has been shared more than 35,000 times with people leaving more than 5,000 comments.
"This breaks my heart and it is so unfair... I'm so sorry, little man I just want to give you big hugs and keep fighting this rotten disease," one Facebook user said.
"Heartbreaking to see this and try to fathom your heartache, but so beautiful to feel the love in this picture," another person added.
Beckett's family has set up a PayPal page for anyone who would like to contribute.
According to the page, Beckett's treatment is expected to last over three years.