"It was Alec's goal to compete at the Olympic trials in 2015," she said.
"He had a very creative side to him that was very unique, and when he put his mind to something, he gave 300 percent," said his mother.
As a middle school art student, he started making wallets out of duct tape, including a "hot pink duct tape jacket" that he wore to a friend's bar mitzvah, according to a McDonogh School profile.
Mr. Cosgarea, a member of McDonogh's Entrepreneurial Club, saw the business potential in his duct tape creations.
He established Duct Tape Outfitters LLC, which sells wallets, flowers, belts, ties, hats, purses, and Kindle cases, all made of duct tape. He donated 5 percent of his company's profits to Swim Across America, which raises money for cancer research.
"Alec was a wonderful member of the McDonogh School family," headmaster Charles Britton said in a statement. "Each day he came to school with a smile that instantly spread to everyone he met. We are grateful to have had the opportunity to know him as a student, an athlete, and a friend to his peers."
"He was just a great young man," said Mr. Ward.
Mr. Cosgarea was a communicant of the Roman Catholic Community of St. Francis Xavier in Hunt Valley.
A Mass of Christian burial will be offered at 10 a.m. Saturday at the Roman Catholic Cathedral of Mary Our Queen, 5200 N. Charles St.
In addition to his parents and brothers, Mr. Cosgarea is survived by his paternal grandparents, Andrew and Rosemary Cosgarea of Falls Church, Va.; and his maternal grandmother, Irene Sullivan of Cleveland.