Fredrick Brennan, 19, moved out of his mother’s home in New Jersey in August and into an apartment in Brooklyn that his boss helped him find. This leap was far greater than the 120 miles or so on a map.

Mr. Brennan was born with osteogenesis imperfecta, commonly referred to as brittle bone disease. A defect in his genes stunted his growth. Below his head and barrel chest are shrunken, bowed stumps for legs and tiny arms twisted after multiple fractures. He said he has broken bones 120 times — “just an estimate.”

He operates his motorized wheelchair with a joystick near his right hand. He spends most of his day at his computer, creating code for new websites for a company called Razor Clicks.

He is quick to smile, even as he tells of what happened to him on Jan. 1 and, perhaps worse, what happened on the next day, when things were supposed to be looking up. His was a bizarre odyssey of naïveté and determination, a whiplash of labels: helpless robbery victim, empowered accuser, and then, helpless again. The police did their best to help him, moving fast and at one point performing a thoughtful, even tender gesture, but then they let him down.