(NewsNation) — It’s been just over one year since U.S. Marine Glenn Osterman lost his best friend, Cpl. Humberto Sanchez, during a suicide bombing attack in Kabul, Afghanistan.

“My world got turned upside down,” Osterman said of Sanchez’s death.

Osterman, now 23, finished five years of military service in August.

The end of his military service led his mother Kristine to say she felt like she could breathe for the first time in years.

Kristine Osterman’s children were small when her husband, an Emergency Services officer, survived 9/11.

When her son was deployed to Kabul in the closing days of the 20-year war, she says she took Xanax and didn’t watch TV. Then she heard about 13 soldiers killed, 200 yards from her son’s tent.

“Every day, I think about those families,” Kristine Osterman said. “And I feel that’s kind of like a survivor’s guilt for a mom. Why was it her son and not mine?”

Glenn Osterman’s family attended Sanchez’s funeral in Indiana and Livestreamed it to Glenn.

Sanchez was a proud Mexican-American.

“I just want everybody to remember that freedom is not free,” said Coral Doolittle, Sanchez’s mother. “He was special, and now, we miss him.”

Glenn Osterman became a volunteer firefighter at 17 and thinks his first responder work helped a little to prepare for the trauma of war.

He was deeply moved by a girl who evacuated with her family from Afghanistan to Italy.

“She brought kind of a light to our dark times,” Glenn Osterman said. “She would always come over to us and hug us and high five us. Whenever we had snacks, we would give them to her and her siblings.”

Osterman’s sister’s friend, Brianna Ventura, became Glenn’s support system when it was difficult to communicate.

“In the iPhone, you can do notes, so I would write to him every day,” Ventura said. “I feel it was good for us, because we got to know each other at deeper levels.”

The two are now a couple, with Glenn Osterman hoping to pursue a law enforcement career in Virginia.  He also wants to stay connected to his fellow Marines. 

“There are guys now who are struggling, they were diagnosed with PTSD,” Glenn Osterman said. “Some people, it will take 20 years before it affects you.”

Glenn Osterman says his religious faith got him through some tough ordeals.

“I’m just lucky every day I’m alive,” Glenn Osterman said. “You realize how lucky you are to be in this country.”