The sister of missing Laverton man Reginald Foggerdy, who was found alive on Tuesday morning after being lost in the outback for nearly a week, said medical teams could not give assurances on his state of health.
Police superintendent Andy Greatwood said early indications suggest the 62-year-old grandfather survived without water and was forced to eat black ants.
"[He was] extremely dehydrated, a bit delusional, but he's received treatment, first aid, on the ground and it's fair to say he's now sitting up and talking, so it's looking very positive," he told 720 ABC Perth.
"His last couple of days of survival were achieved by lying down under a tree and eating black ants, so that's the level of survival that Mr Foggerdy has gone to.
"[He had] no water whatsoever for six days."
Mr Foggerdy's sister Christine Ogden told Radio 6PR on Tuesday morning she was yet to speak with her brother.
"I haven't chatted [to him], I don't think we'll be able to for a little while," she said.
"[Medical teams] can't give any assurances, he's been out there for quite some time, he's so dehydrated, he wouldn't be able to communicate with us.
"It's up to the medical team now."
Ms Ogden said police trackers found the her brother between 5am and 6.15am on Tuesday morning after spotting fresh footprints during their search on Monday afternoon.
"They must have been very close to him [when Monday's search finished]," she said.
"He had stopped walking."
"[The searchers] never lost faith, I was so impressed with the service – they are just amazing people."
Mr Foggerdy will be transferred to a nearby hospital by the Royal Flying Doctor Service.
Helicopter pilot Darren Rowtcliff, who had been part of the search since Friday, said the chopper's lights may have inadvertently played a part in Mr Foggerdy being found.
Mr Rowtcliff said he had been "orbiting" the helicopter, using its lights to guide rescue teams through sand dunes.
Track marks, believed to be Mr Foggerdy's, were later found to have "changed course dramatically... toward the area we had been orbiting," he said.
Mr Rowtcliff said the police trackers were "phenomenal", however during such searches "we really need to send up flares" after nightfall.
More than 40 police and SES personnel were involved in land and air searches for the man after he went missing during a hunting trip 170 kilometres east of Laverton on Wednesday.
