SEOUL, South Korea -- Kim Kwang Ho left his hometown in North Hamgyong Province, now North Korean territory, when he was in middle school, leaving his mother and younger brother behind. He left without a single photo, believing he would be back within 10 days, when the danger of war dissipated. Those 10 days turned into 68 years.

Kim, who is now 80, still has clear memories of his hometown, recalling the apricot trees that grew in his backyard. But he says he cannot recall the faces of his mother or little brother. Nevertheless, his longing for his family always stayed with him: “When I hear the word ‘mother’ I just cannot help but cry.”

On Monday, Kim and others chosen by lottery will finally rejoin family members from the North they haven't seen in decades. The winners of that lottery -- held between the North and South as part of cooling tensions between both sides -- passed a screening to become the final 89 South Koreans to meet their families in the North for three consecutive days. And conversely, starting Friday, 83 North Koreans will get three days to meet with their separated families who are living in South Korea.

Lee Su Nam was astounded when Red Cross delivered the message that he will be meeting his older brother. He is now 77 years old and had only faint hope that his brother -- 10 years older than Lee -- would still be alive in the North. Lee’s family lived in South Korea for generations. One morning, his older brother was taken away by the North Korean military, and Lee has never forgotten that day.

“For me it was just my older brother that I lost, but for him it was the whole family -- hometown, friends, school ... everything. I can’t imagine how hard his life must have been,” Lee told ABC News, as he clutched old photos of his big brother, which Lee had kept all these years.

So far, 132,603 people have registered with the Red Cross for cross-border family reunion. Fifty-seven percent of them are now dead. And among the 56,862 seniors who are still waiting for a reunion, 63 percent of them are over 80.

“There are still over 50,000 people who haven’t seen their loved ones yet,” 92-year-old Yoon Heung Kyu said. He left his home in North Korea several years before the Korean War broke out. Although his roots were in the North, he had to fight along with South’s army.

“This meetup is a good thing and we should do it,” he said. “But instead of going to Mount Kumkang, they could build a fort at Panmunjom and let people see their loved ones much more freely.”

Jeong Hak Soon, 81 years old, is meeting her older brother’s wife and son on Monday at the reunion area. To her dismay, her much-missed brother was no longer alive to give her a pat on her head once again. She choked back tears talking about how her warm-hearted older brother was taken by the North Korean military. Her family evacuated their home in the North, not knowing they would never have their real home back.

“He [my brother] would have returned to an empty house,” Jeong said. “I wonder how he managed to live on his own in that big empty house. My heart breaks every time I think of it.”

Jeong holds hope that inter-Korean relations will improve amid the currently thawing atmosphere.

“I sincerely hope for unification,” Jeong said. “I really wish I could meet them, visit their place, bring them here, and feed them some good food.”

The official reunions event between families in the two Koreas began in 2000. So far 4,120 families were given the chance to meet their family members still in the North through 20 reunion events that took place at Mount Kumgang in North Korea. The last reunion of separated families took place in 2015.

ABC News' Sunwoo Kim and Soohyun Kim contributed to this report.