“I was in shock,” she said. “I just jumped in a cab and got there as soon as I could.”

For Ms. Chyun, a freelance graphic designer who graduated from the University of the Arts in Philadelphia and received a master’s degree in communication design from Pratt Institute, helping Mr. Gillman recover from his near-death experience became a study in faith, and a primary reason to live.

“When Michael was ill, Elle nurtured him every day,” said Mr. Gillman’s mother, Wendy Gillman. “Though Elle realized she wasn’t legally responsible for him, she still stepped up as much as she could. I would stay at the hospital overnight, and every morning, Elle would bring me breakfast. I had to keep convincing her to go back to work and take care of herself, but no matter what, she would always return immediately after work. There was just so much love for Michael in her heart.”

Deborah Chyun, the bride’s mother, recalled the pain suffered by both families during those dark, uncertain days. “We were all so worried about Michael,” she said, her voice beginning to crack as she watched her daughter and new son-in-law take turns gleefully signing legal documents at the conclusion of the ceremony.

“I could see how much Elle cared for Michael in the way that she stood by his side,” Ms. Chyun said. “I’m just so happy that this day has arrived for both of them.”

Mr. Gillman, who graduated from Rochester Institute of Technology, is the vice president of technology at Acadaca, an e-commerce consultancy in New York. When he first met Ms. Chyun in October 2012, she was attempting to weather a different kind of storm.