Terry Sinclair told a coroner's inquest on Tuesday that he hasn't been back to work since Dylan LaChance, 16, died the night of Sept. 18, 2013.
The inquiry has been told the teen was taken to the facility after a fight outside the high school on the Big River First Nation, and that even staff who knew sign language had difficulty communicating with him.
Sinclair recalled noticing the youth was pale, sweating profusely and shaking in his cell, saying he felt the boy's eyes were saying: "Help me."
He says as he alerted a supervisor of the need to get LaChance to hospital, the boy's brother Skyler, who was in a nearby cell, started yelling that Dylan was vomiting.
Sinclair says the youth was soon vomiting blood and then lost control of his bladder.
He stayed with the boy in the ambulance and in hospital, where LaChance's heart rate and blood pressure rose.
Sinclair became emotional while recalling how LaChance fought to draw air, saying that the doctors and nurses were crying while working to keep him alive.
After the boy was pronounced dead, Sinclair went back to work, picked up his lunch kit and went home: "I haven't been back since."
He expressed remorse at the inquest, saying he wishes he could have done more.
Angie Bear, who is not related to Dylan LaChance but is representing his family at the inquiry, suggested that as a mute and deaf teen, the cell he was held in "must have been a very lonely place."
Sinclair tearfully nodded in the affirmative, saying he doesn't think it's fair someone with LaChance's needs should be in a place without the resources to accommodate those needs.
Dr. Shaun Ladham, who performed the autopsy on LaChance, said the boy died of acute bronchopneumonia and may have developed the lung infection very quickly.
The inquiry has previously heard testimony that LaChance complained of back pain early in the week he spent at the youth facility, and was taken to a walk-in clinic where a doctor diagnosed it as a soft-tissue injury and prescribed an anti-inflammatory.
Dr. Nico DeBeer testified he does not recall the specific visit, but said his notes indicated a caregiver told him LaChance had been kicked in the back.
DeBeer's note also said he'd checked his lungs with a stethoscope and noticed nothing abnormal.
If Dylan had pneumonia at the time his lungs would have made a "crackle" noise and bronchitis would present with a "wheeze" through the stethoscope, DeBeer said.
DeBeer said he did not take bloodwork, which may have revealed Dylan's underlying conditions.
The inquest, which is mandatory when anyone dies in custody, will conclude with recommendations to prevent similar deaths in the future.