Chiang Rai, Thailand (CNN) The 12 boys who were trapped in a cave in northern Thailand for almost three weeks paid tribute to the Navy SEAL who lost his life during the rescue operation.

Wiping away tears, the boys wrote messages of thanks on a portrait of the former Navy SEAL Saman Kunan , who died July 6 during an operation to deliver oxygen tanks to the trapped teens and their coach.

Kunan, 38, ran out of air while underwater, an official said at the time.

Ex-Thai Navy SEAL Samarn Kunan died while trying to deliver oxygen tanks to the trapped soccer team.

His death came at a pivotal moment in the rescue operation, as teams ramped up their efforts to free the boys ahead of forecast monsoonal rain and dropping oxygen levels in the cave.

Doctors decided last week to ask the boys' relatives to tell them about the death of Kunan, according to the Thai Public Health Ministry's permanent secretary Dr. Jedsada Chokedamrongsook.

A team of psychiatrists was also on hand to monitor their mental health, the doctor said.

The boys, ages 11 to 16, wrote messages of thanks and promised to be "good guys" on a portrait of Kunan.

The boys promised to be "good guys."

All the members of the Wild Boars soccer team are in good health and are expected to be discharged from hospital by Thursday, the Health Ministry said in a statement Saturday.

"I understand that everyone is worried and have good wishes for them," Dr. Chokedamrongsook said.

"(We) don't want to blame or accuse anyone (of their ordeal). I want this time to become a period to help or support each other -- to be a beautiful moment for all people across the country," Chokedamrongsook added.

JUST WATCHED The story of the Thai cave rescue Replay More Videos ... MUST WATCH The story of the Thai cave rescue 10:44

The boys and their 25-year-old coach were freed over three days last week, bringing to an end a complex rescue mission involving hundreds of experts from across the world.

The soccer team became trapped deep inside the Tham Luang cave network during an outing on June 23, after a sudden rush of flood water cut them off.

They were discovered nine days later by two British divers, perched on a small ledge of dry land about 4 kilometers (2.5 miles) from the cave's entrance.

Boys 'just wanted to visit the cave for an hour'

Tanawat Viboonrungruang, the father of the youngest boy, 11-year-old Chanin, told CNN on Friday that his son had just wanted to "visit the cave for an hour."

But after the flash floods, the boys and their coach ran deep inside the cave, where they became trapped.

Photos: Photos: Thai soccer team rescued from cave The rescued team attends a news conference in Chiang Rai, Thailand, after being discharged from the hospital on Wednesday, July 18. Hide Caption 1 of 54 Photos: Photos: Thai soccer team rescued from cave Members of the soccer team greet well-wishers as they arrive for the news conference on July 18. Hide Caption 2 of 54 Photos: Photos: Thai soccer team rescued from cave The team poses with a sketched portrait of Saman Kunan, a former Thai Navy SEAL who died on July 6 while returning from an operation to deliver oxygen tanks to the cave. He ran out of air while underwater, an official said. Hide Caption 3 of 54 Photos: Photos: Thai soccer team rescued from cave Thai Navy SEALs pose for a photo after the rescue effort was finished on July 10. One of them was a doctor who stayed with the team for a week after the group was found alive on July 2. Hide Caption 4 of 54 Photos: Photos: Thai soccer team rescued from cave Rescuers carry one of the boys out of the cave. Hide Caption 5 of 54 Photos: Photos: Thai soccer team rescued from cave Divers wave through floodwaters in the cave. Each rescue took multiple hours. Hide Caption 6 of 54 Photos: Photos: Thai soccer team rescued from cave Chiang Rai Governor Narongsak Osotthanakorn speaks during a news conference held after the rescue was finished on July 10. Hide Caption 7 of 54 Photos: Photos: Thai soccer team rescued from cave A helicopter transports rescued boys to the hospital on July 10. Hide Caption 8 of 54 Photos: Photos: Thai soccer team rescued from cave People watch and cheer as a helicopter flies toward an airstrip to transport one of the rescued boys to a hospital. Four boys were rescued on July 8, another four were rescued on July 9, and the rest were rescued on July 10. Hide Caption 9 of 54 Photos: Photos: Thai soccer team rescued from cave Rescue workers leave after all members of the team had been saved. Hide Caption 10 of 54 Photos: Photos: Thai soccer team rescued from cave This photo tweeted by tech entrepreneur Elon Musk shows rescue efforts during the three-day mission. Musk tweeted early July 10 that he had visited the cave and left a mini-submarine there for future use. Hide Caption 11 of 54 Photos: Photos: Thai soccer team rescued from cave Members of the Royal Thai Navy are pictured with the team inside the cave. Hide Caption 12 of 54 Photos: Photos: Thai soccer team rescued from cave The boys received medical attention after being found alive on July 2. Hide Caption 13 of 54 Photos: Photos: Thai soccer team rescued from cave An ambulance believed to be carrying one of the rescued boys heads to the hospital on July 10. Hide Caption 14 of 54 Photos: Photos: Thai soccer team rescued from cave Rescuers walk toward the entrance of the cave as rescue operations resumed on July 10. Hide Caption 15 of 54 Photos: Photos: Thai soccer team rescued from cave Hospital staff and a police officer are seen during a news conference that was held on July 10. The eight boys that had been rescued on July 8 and 9 were being treated in an isolation ward in a Chiang Rai hospital. Hide Caption 16 of 54 Photos: Photos: Thai soccer team rescued from cave Thai police and military officers use umbrellas to shield a rescued boy before he was transported to a hospital on July 9. Hide Caption 17 of 54 Photos: Photos: Thai soccer team rescued from cave An ambulance exits the cave area on July 9. Hide Caption 18 of 54 Photos: Photos: Thai soccer team rescued from cave Emergency responders surround a helicopter on July 8. Hide Caption 19 of 54 Photos: Photos: Thai soccer team rescued from cave Rescue teams arrange a water-pumping system at the cave's entrance on July 7. Hide Caption 20 of 54 Photos: Photos: Thai soccer team rescued from cave Ambulances wait outside a hospital where the rescued boys were treated. Hide Caption 21 of 54 Photos: Photos: Thai soccer team rescued from cave Thai military personnel walk into a cave during rescue operations. Hide Caption 22 of 54 Photos: Photos: Thai soccer team rescued from cave Military personnel work inside a cave. Hide Caption 23 of 54 Photos: Photos: Thai soccer team rescued from cave An ambulance leaves the scene of the rescue effort on July 8. Hide Caption 24 of 54 Photos: Photos: Thai soccer team rescued from cave This undated photo, released via the Thailand Navy SEAL Facebook page, shows rescuers with their hands locked. The caption said, "We Thai and the international teams join forces to bring the young Wild Boars home." The Wild Boars is the name of the soccer team the boys play on. Hide Caption 25 of 54 Photos: Photos: Thai soccer team rescued from cave Family members pray in front of a Buddhist statue near the cave on July 8. Hide Caption 26 of 54 Photos: Photos: Thai soccer team rescued from cave Emergency workers carry oxygen tanks as rescue operations begin. Hide Caption 27 of 54 Photos: Photos: Thai soccer team rescued from cave Thai soldiers work to connect pipes that help water from entering a cave. Hide Caption 28 of 54 Photos: Photos: Thai soccer team rescued from cave Thai forest rangers examine a map as they review their rescue options on July 8. Hide Caption 29 of 54 Photos: Photos: Thai soccer team rescued from cave This image, taken from video on July 2, shows the team trapped inside the cave. That was the day divers found them alive. Hide Caption 30 of 54 Photos: Photos: Thai soccer team rescued from cave Divers were able to bring food, blankets and other supplies to the boys while experts determined the best way to get them out safely. The team was found around two kilometers (1.24 miles) into the cave and somewhere between 800 meters to one kilometer below the surface, according to a British Cave Rescue Council briefing note. Hide Caption 31 of 54 Photos: Photos: Thai soccer team rescued from cave The team was found alive by British divers. The search brought rescue teams from all over the world. Hide Caption 32 of 54 Photos: Photos: Thai soccer team rescued from cave A Thai military medic provides first aid to one of the boys. Hide Caption 33 of 54 Photos: Photos: Thai soccer team rescued from cave The body of Saman Kunan, a former Thai Navy SEAL, is carried during a repatriation and religious rites ceremony on July 6. Kunan died Friday as he returned from an operation to deliver oxygen tanks to the cave. He ran out of air while underwater, an official said. Hide Caption 34 of 54 Photos: Photos: Thai soccer team rescued from cave Thai police take a break for breakfast as rescue operations continue on July 4. Hide Caption 35 of 54 Photos: Photos: Thai soccer team rescued from cave Water is pumped out of the cave on July 3. Hide Caption 36 of 54 Photos: Photos: Thai soccer team rescued from cave Workers fix the road leading to the cave on July 3. Hide Caption 37 of 54 Photos: Photos: Thai soccer team rescued from cave Divers prepare a light to be used for the underwater search on July 2. Hide Caption 38 of 54 Photos: Photos: Thai soccer team rescued from cave Rescue workers wait at the entrance to the cave on July 2. Hide Caption 39 of 54 Photos: Photos: Thai soccer team rescued from cave Some of the team's family members celebrate after receiving news that the team was alive. Hide Caption 40 of 54 Photos: Photos: Thai soccer team rescued from cave Technicians lift water pumps to the drilling site on July 1. Hide Caption 41 of 54 Photos: Photos: Thai soccer team rescued from cave Soldiers and rescuers work outside the cave complex on July 1. Hide Caption 42 of 54 Photos: Photos: Thai soccer team rescued from cave Monks attend a Buddhist prayer for the team on July 1. Hide Caption 43 of 54 Photos: Photos: Thai soccer team rescued from cave Scuba tanks are delivered to the search site on July 1. Hide Caption 44 of 54 Photos: Photos: Thai soccer team rescued from cave Rescue workers carry water-pumping equipment into the cave on July 1. Hide Caption 45 of 54 Photos: Photos: Thai soccer team rescued from cave A Thai Air Force worker drops near a possible cave opening on June 30. Hide Caption 46 of 54 Photos: Photos: Thai soccer team rescued from cave British cave diver Robert Charles Harper explores an opening on June 29. Hide Caption 47 of 54 Photos: Photos: Thai soccer team rescued from cave Relatives of the trapped team members pray on June 27. Hide Caption 48 of 54 Photos: Photos: Thai soccer team rescued from cave Family members waited more than a week for news of their loved ones. Hide Caption 49 of 54 Photos: Photos: Thai soccer team rescued from cave Thai soldiers bring hoses and additional water pumps as the search for the team continued on June 27. Hide Caption 50 of 54 Photos: Photos: Thai soccer team rescued from cave Volunteer paramedics wait near the cave entrance on June 27. Hide Caption 51 of 54 Photos: Photos: Thai soccer team rescued from cave A rescuer looks for a cave entrance on June 27. Hide Caption 52 of 54 Photos: Photos: Thai soccer team rescued from cave Rescuers search the cave on June 26. Hide Caption 53 of 54 Photos: Photos: Thai soccer team rescued from cave Thai soldiers relay cable at the search site on June 26. Hide Caption 54 of 54

Viboonrungruang said his son, nicknamed Titun, had told him their coach, Ekkapol Ake Chantawong, had told the boys to run away from the water and go to higher ground.

Inside the freezing cave, the coach and another boy hugged Titun to keep him warm, said his father.

After more than week trapped in the cold and dark, they finally saw a flash light. The boys came down from a small hill inside the cave and shouted for help.

Parents of the boys have since been advised by doctors not to speak to the press for at least a month, as they recover from the traumatic experience.