Big Brother star Reggie says her fatally sick son asks her 'what heaven is like'.

Reggie Sorensen (formerly Bird) now leads a life that is far cry from the bizarre, technicolour circus that was Big Brother. Thirteen years on from her popular win, she’s facing a struggle beyond what most could even imagine.

A sufferer of a congenital eye condition, she will go blind within a matter of years. But, as she revealed on A Current Affair, worse than the thought of losing her vision, is the thought of losing her son.

Seven-year-old Lucas has Cystic Fibrosis – a life-threatening, genetic condition that causes sticky mucus to build up in the lungs. He requires daily physio, and often struggles to breathe – something people are surprised to hear when they meet the active little boy.

“They all look at him and go, ‘Gee you don’t look sick’, but inside it’s a different story,” Sorensen told the programme. “He’s battling a big fight to stay alive.”

Lucas Sorensen, during one of his many hospital visits. Image: Facebook.

On top of all that, the Tasmanian mother of two is tangled in red tape that means she - as a blind person - can obtain financial support under the National Disability Insurance Scheme, while her son is ineligible.

"We've been forgotten," she told A Current Affair. "I just don't want us to be left out. We need help."

The cost of Lucas' treatment is immense - just one month's worth of one of a single medicine costs $2000, the therapy machine he uses daily is worth $8000, and soon he'll require a feeding tube to help him put on weight.

"There's many people out there who are going blind who also have to be a full-time carer as well," Sorensen said.

Reggie and Lucas. Image: Facebook.

While it's unclear how long Lucas will live, most CF sufferers don't survive beyond 30 - and they're the lucky ones. Sorensen has thus made an effort to speak openly and honestly about mortality with her boy.

"I used to think 'Oh my God, how do I talk about this?', but now it's just normal to talk about dying," she said.

It's a daunting concept for a child to comprehend, and perhaps even more so for many adults. But Lucas is wrapping his mind around it as best as a seven-year-old can - he even told ACA reporter that "only Santa Claus lives forever".

"He says, 'Mummy, what's it going to be like in heaven?', and 'Are there Pokemon cards in heaven?'" Sorensen told A Current Affair.

"[I tell him] that it's going to be okay, and things are going to be good. I know I'm probably lying - I don't know what's on the other side. But he's a little angel, so I'm sure he's going to be looked after."