The last time anyone saw Ho Van Thanh, in 1973, he was running into the woods with his infant son after a bomb exploded near his home in Vietnam during the Vietnam War.

Forty years later, the 82-year-old man and his 41-year-old son have been found in a forest in the Tay Tra district of Quang Ngai province. Two people from a nearby village were looking for firewood when they came upon the pair's tree house, Times Live reports.

"My uncle doesn't understand much of what is said to him, and he doesn't want to eat or even drink water," Thanh’s nephew, Ho Ven Bien, told the Herald Sun. "We know he wants to escape my house to go back to the forest, so we have to keep an eye on him now."

Thanh could reportedly communicate in the Cor ethnic minority language, but his son, Ho Van Lang, spoke only a few words. The pair reportedly fled to the forest after a mine explosion killed Thanh’s wife and two other children four decades ago.

The father and son were found by local villagers who wandered 25 miles into the woods. They found the men living in a tree house. Photos taken by local media show the younger man wearing a loincloth made from tree bark, looking thin and disheveled.

"My father is very weak and the doctors are taking care of him, but my brother's health is fine even though he looks very thin," Ho Van Tri, Thanh’s son, who was left behind when his father fled into the forest, told the Herald Sun. He was 6 months old at the time.

The two men reportedly survived by eating forest vegetables and hunting animals. Their house, which resembled a bird's nest, was made from sticks surrounded by a large tree near a stream. The pair also made tools such as knives, axes and arrows for hunting, Thanh Nien News reports.

While some reports said the pair had no contact with the outside world all this time, Yet Ho Van Tri, Thanh’s youngest son, says he found his father and brother 20 years ago but could never persuade them to leave their jungle home, according to VnExpress. Tri said he has visited the pair every year and offered them salt and oil, which they have refused to accept.

Villagers say the discovery of the father and son has shaken their small community, which had believed the pair was long dead. "No one could imagine Thanh and his son could live 40 years in isolation in the hard conditions of the jungle," villager Ho Van Xanh said.