"He absolutely loved his country, definitely believed in what he was doing, and wanted his family to be strong," said William Mann, 31.
"I think I'm still in shock. It doesn't seem real. I still think I'm going to see my brother."
About two weeks ago, Lt. Mann rushed to a crashed helicopter and pulled a pilot from the wreckage as fuel spilled on the ground, raising fears of explosion.
"He was definitely a hero, and the sad part is that he was a hero before the helicopter crash; he was a hero to all of us," William Mann said. "Pulling the pilot from the helicopter was everyday business to him."
Mann said his brother was "in his accommodations at a forward-operating base while British engineers were working on the facility, and the roof collapsed. It's still under investigation. I don't know whether they realized he was in there."
Marines went Thursday to the home of his mother, Alfina Mann, in Woodlynne to break the news of her son's death.
"I understand accidents," said William Mann, a former Army sergeant who spent 10 months in Iraq during and after the invasion in 2003. "It's an unfortunate mess.
"He was highly trained and such a smart kid. He was quick on his feet and definitely could handle himself. This was the only way they would get him."
Jason Mann was chubby and reserved in high school, but became athletic and more outgoing when he joined the military, William Mann said.
"He broke out in the Marines," said his brother. "People didn't know him. He went from not being involved in anything to doing marathons. He did the most rigorous training and excelled at it."
Jason Mann graduated from the University of South Carolina with a finance degree and from his Marine Corps officer's class with top honors. He was later assigned to the First Battalion, Sixth Marines, 24th Marine Expeditionary Unit, II Marine Expeditionary Force, with headquarters at Camp Lejeune, N.C.
"He loved the decisions he was making and continued on his path," said William Mann. "But he was torn between family and country.
"His wife and child were his top priority; at the same time, he was definitely a true Marine. His wife understood and stood behind him."
Shannon Mann and the couple's daughter were spending the Independence Day holiday with William Mann and his family when Jason called July 6 from Afghanistan to his wife's cell phone.
"She gave me the phone, and I asked him how he was doing and told him to 'keep yourself safe and don't let your guard down.' "
Jason Mann hoped to finish 20 years in the Marine Corps and then, using his leadership skills and educational background in finance, become chief executive officer of a company.
"He was a leader in the Marines and wanted to be a leader afterward," said William Mann. "He wanted to buy a house someday for his family."
In addition to his wife, child, mother and brother, Jason Mann is survived by his father, Orville, and a sister, Jennifer Cleaver.
"His life was too short," said William Mann. "I want people here to know of his sacrifice and his loss.
"He had such high goals and expectations, so many plans, so many things to accomplish. He lived 100 percent in the moment."
Contact staff writer Edward Colimore at 856-779-3833 or firstname.lastname@example.org.