Fortune has not been kind to the Whitehead family.
They love their Mallee home and each other, all the more given the pressures they endure together.
For both Shelbie, aged 12, and Jackson, eight, the diagnosis was neurofibromatosis: a complex genetic condition with a range of symptoms.
Shelbie has holes in her skull where the bone has decalcified, while Jackson has scoliosis and trouble seeing; both also live with tumours and learning difficulties and experience recurring pain, among other challenges.
Jackson needs constant noise and action to stimulate his senses, while Shelbie likes peace and quiet.
Both still live happy lives, going to school, watching TV and playing with their dog Ringer.
But it has been a hard slog for them, their mother Kirsty and her husband Paul.
"We deal with a lot of unknowns ... we don't know how long we've got them," Kirsty said.
"To have your little girl come up to you and ask, 'Am I going to die...?'"
Wearily she described the childhood challenges Shelbie had faced, the seven times she nearly lost Jackson to pnemonia before he was three, and the years of doctors' visits and hospital stays it took to find out what had caused their troubles.
"We've always had specialists, we've always been going up and down to hospital, but only in the last few years has it been so often," she said.
"We've had 10 specialists between them, if not more.
"We're at hospitals almost weekly, sometimes two or three a week."
They try to give the siblings as normal a life, as many good memories and as much happiness as possible.
Kirsty quit work to care for her children and moved them from Murray Bridge to Geranium, an environment that has benefited their health despite its isolation.
"There's no traffic, they can go outside, ride their bikes, just be kids," Paul said.
"Since then he (Jackson) hasn't gone into hospital, not for pneumonia; he's got a lot stronger, he can ride up the hill instead of being pushed."
But little things can still hit the family hard, and recent car troubles led them to turn to an online fundraising site.
"There's a lot of people worse off than we are," Paul insisted.
"We're not looking for a handout; we're just at a point where we need a little bit of help."
- Help out: Visit www.gofundme.com/2jj4us4.