The 26-year-old, who grew up in the Logan section of Philadelphia, was killed by a bomb in Afghanistan on Tuesday.
He was serving his first combat tour in Afghanistan, where he had arrived in early January.
He leaves behind a wife and 6-month-old son Christopher.
Family members say he was an honorable and religious man devoted to the military.
Frison was just promoted to 1st Lieutenant on April 10th - his birthday.
He enlisted only two years ago.
"He knew exactly what was going on. Some of his last Facebook messages and some of his last e-mails showed great dignity, great pride, in what he was doing for his country," Demetrius' brother Paul Frison said.
Sgt. Roberto Brabham had been friend with Frison since high school days in Philadelphia.
"He died loving serving his country. He died a very honorable and noble death and his family is very proud of him, I know I'm proud of him, and we encouraged his step into the military," Sgt. Brabham said.
"There's nothing that I would change about his decision. I supported my brother 110%. I love my brother 110%. I'm going to carry my love right over to little Christopher," Paul said.
