When Allison Langdon thinks back to her childhood with her little sister, Kristen, she has idyllic memories of them playing with their brother, mucking around in bushland "down the back" of their family's property in Wauchope, NSW.
But the Today host has other memories mixed among them. Of Kristen spending lunchtimes in the school office drawing up her insulin, of watching her take pinpricks and have her thrice-daily injections.
Kristen had been diagnosed with diabetes at the age of 11.
"Growing up, we were always mindful of it," Allison said. "If Mum and Dad were out or we were off somewhere with Kristen and she had a sugar-low it could be quite dangerous. We all had to know what to do in such circumstances.
"But most of the time, she took care of it. She took care of it so well."
In 2010, shortly after Kristen gave birth to her first child, a little girl who arrived 13 weeks premature, Kristen's health deteriorated.
As she writes for Mamamia, by the following year, it became clear she needed a kidney transplant.
"The first four years of [my daughter's] life, she did not have a healthy mum. I was constantly exhausted as my body struggled with the buildup of toxins that my failing kidneys couldn’t process. For years, that was my life until the decision was made in early 2014 that I needed dialysis."
Watching her sister hooked up to machines daily, waiting for a new chance at life, left Allison heartbroken.
"She couldn't run around and do all things that she wanted to do with her little girl... She's such a beautiful mum. She's the most extraordinary mum, with just so much love to give," Allison said.
"She's stoic, she's strong, but it was hard; it was hard to watch it and to feel like you couldn't do anything to help."