He’s served in the military since his teenage years, has fought Australia’s enemies in brutal war zones – and now he’s fighting an enemy inside his own head.

Mr Fewson, who is well-known to scores of Wagga people as a high-profile gym instructor, believes he has an illness known as Traumatic Brain Injury (TBI).

It’s a devastating blow on two fronts: very little is known about TBI and the illness is strengthening its grip on his life.

It’s a race against time.

“It’s been a massive turnaround in the last 12 months,” Mr Fewson said. “The decline has been rapid and bad.”

Mr Fewson links his condition to blackouts sustained on tours of duty by blasts let off from improvised explosive devices.

He compares the illness to a football player being exposed to “constant concussion” during game time.

“Our body is our life; we can shape it and mould it to whatever form we like,” Mr Fewson said. “The only thing you can’t change is what’s in your head.”

Mr Fewson can have up to two “random” seizures in a day, his speech is slurred and memory loss is becoming more common.

His doctors have scrambled for a diagnosis.

“We’re just blind – we’re totally blind. And it’s not their fault – we have no experience of TBI in Australia,” he said.

There is no “magical treatment” for TBI, but Mr Fewson points to medical efforts under way in the United States.

The US is said to be “streets ahead” of Australia on TBI research because a large chunk of its army has succumb to symptoms similar to Mr Fewson’s.

“Can it be maintained, can I slow it down or is it just going to decline?” he said.

“That’s what we want to know.”

Mr Fewson’s family have started a crowd-funding campaign with a view to fly him to the US for treatment. It can be found at gofundme.com/yf7yu2g.