Claire Derry reached the bedside of her 18-year-old son, Sam Derry-Woodhead, on Saturday at Longreach Hospital in northeast Australia, where he is recovering from dehydration.
She said she feared the worst while flying from London's Heathrow Airport to Longreach until she was told during a stopover in the east coast city of Brisbane that searchers in a helicopter had winched her son to safety on Friday.
"He'd survived on fluid from contact lenses and his own urine," Derry told Ten Network TV. He was sunburned and had lost 15 kilograms (33 pounds), she said.
Derry-Woodhead, who's from Richmond upon Thames, outside London, became lost in scrubland while jogging Tuesday near Upshot Station, a cattle ranch 90 kilometers (55 miles) from Longreach.
He had been working at the ranch for less than two weeks as a novice cowboy known in Australia as a jackaroo.
Temperatures reached 40 degrees Celsius (104 Fahrenheit) as around 50 searchers scoured the rugged terrain over three days. Two searchers received medical treatment for heat stroke.
Alex Wright, who was part of the crew that rescued Derry-Woodhead, said they were lucky to spot him through the trees 6 kilometers (4 miles) from where he became lost.
"We just happened to see him as he was crossing a clearing," Wright told Ten. "He's been dehydrated. Everything about him, all of his features, looked very sunken."
George Thomson, another rescue crew member, said Derry-Woodhead thanked them after being winched aboard the helicopter and asked for a popsicle.