Three weeks after a 25-year-old hunter and his friend died of a lightning strike in the southern Colorado wilderness, his grieving mom is sharing details of her last time with her son — and how she endured the days-long search for the missing men.

“Spiritually, I believe that there’s a reason that things happen,” Michelle Sirch tells PEOPLE after the death of her son, Ian Stasko, and his 25-year-old friend, Andrew Porter, who were missing for days before their bodies were found on Sept. 18 in the Rio Grande National Forest.

“I have wondered if his soul felt like, ‘I don’t think I can do the changes that I’m here to do while I’m in this body,’ ” says Sirch, a 64-year-old outpatient therapist from Virginia.

Stasko was an avid outdoorsman who was deeply connected to nature. He discovered a love of hunting through Porter, with whom he’d been friends since Little League Baseball.

Both experienced hunters, the pair were in the San Juan Wilderness when they lost contact. Porter had been checking in with his fiancée, Bridget Murphy, every few hours up until Sept. 11, when he last touched base with her through a satellite device, Murphy previously told The Colorado Sun.

By Sept. 13, deputies from the Conejos County Sheriff’s Office arrived at the Rio de Los Pinos Trailhead following reports that the two men were overdue, according to press releases shared with PEOPLE. According to officials, they had “failed to check in with loved ones at a predetermined time.”

A days-long search commenced involving more than 170 people, including search teams on the ground and in the air, people on horseback and canine units. Early on in the search, the men’s vehicle was found at the trailhead with their backpacks and camping gear inside, prompting concern because of the “heavy rain and bad weather,” the sheriff’s office said.

By Sept. 14, Sirch got a call from Porter’s mom that the 25-year-old friends were missing.

“I was terrified,” she recalls. The worried mom immediately booked a flight from Virginia to Colorado, which was an agonizing trip. Sirch remembers crying on the three flights she had to take, followed by little sleep and hours of traveling before she got to the trailhead.

She arrived on Sept. 16, where she was met by other friends and family members waiting for news. Ian’s 20-year-old sister, Dylan Stasko, also booked a flight so she could be present while search and rescue professionals looked for her brother.

“For the next three days, that’s where we were,” Sirch says. Officials didn’t permit them to participate in the search for safety reasons. While they waited, the men’s loved ones saw for themselves how quickly the weather could change.

“It would be beautiful, warm, one minute,” remembers Sirch. “Then, this wind that was really cold would just come from nowhere.” She says her fear persisted from the time she received the devastating phone call to the day her son and Porter were found on Sept. 18.

The bodies of both men were found two miles from the Rio de Los Pinos Trailhead, officials announced. Four days later, Conejos County Coroner Richard Martin confirmed to PEOPLE that the men died after being struck by lightning. He added that their injuries were consistent with “a pretty intense electrical jolt.”

Sirch would later learn that based on the positioning of their bodies, the two men were heading back to their car because the weather was “cranking up,” she says.

“They took a step and lightning just hit at that moment in that spot,” Sirch says. “The coroner said ‘instantaneous,’ which is one way to make peace, knowing that he did not suffer.”

As Sirch mourns her kind son — who had a “gentle soul” and “fearless” love of adventure — she takes comfort in the last days they spent together earlier this year. In January, she and Dylan were in a car accident, and as Sirch healed, her son stayed with her.

“That was lovely,” says Sirch. “I was home recovering, so we were able to have talks about metaphysical things, spiritual things, the world.”

Ian, who was working as a tree climber, also wanted to develop his own business. The young man recognized “our interconnectedness both with one another and with nature,” says his mom, adding that he wanted to “change the world.”

Sirch hopes to publish his writings one day. For now, she and her daughter will attend Porter’s funeral on Sunday, Oct. 5, in Earlysville, Va. She plans on arranging a celebration of life for her own son later this year.

For Dylan, her grief is just as deep, and she plans on honoring everything Ian taught her.

“My life will be forever changed without you,” Dylan wrote in a tribute on Instagram on Sept. 22. “I promise to keep living each and every day for the both of us and continue your goal of changing the world.”

At the end of her ode to her brother, Dylan wrote, “You always loved adventures, and I know that death will be the greatest adventure of them all.”