The wife of a Chicago Fire Department firefighter died Thursday night, two days after the firefighter responded to a fire in his own home and tried to save her with CPR in front of the family’s Montclare house Tuesday night.

The Cook County medical examiner’s office confirmed Friday that Summer Day-Stewart, 36, had died. Her son, 7-year-old Ezra Stewart, died Wednesday night. The couple’s two other children, a 2-year-old girl and a 7-year-old girl, were both last listed in critical condition.

The firefighter, Walter Stewart, heard his own address as the location of the blaze Tuesday night. A Chicago Fire Department chief drove him from a fire station five miles away. First responders found Day-Stewart and the three kids unconscious from smoke inhalation and in grave condition.

[ ‘It’s hard to put into words’: Firefighters rally around colleague after tragic fire kills 1 child and rest of family clings to life ]

Outside his burning home, the young firefighter performed CPR on his now dead wife, Fire Department spokesperson Larry Langford said.

“It’s gotta be like hell,” Langford said. “We’re doing all we can to support him.”

There were no new updates on the condition of Stewarts two other children, Langford said.

The investigation into the fire was undetermined and suspended Friday, though it remained possible that investigators would do a forensic analysis of artifacts from the fire, Langford said.

The veteran fire spokesperson said he had never seen anything like the nightmare scenario in his many years with the department. Firefighters’ homes have caught on fire, he said. Even fire stations have caught fire, he added.

But Langford said he couldn’t remember the department facing a tragedy like this.

“As long as I’ve been associated with fires, I can’t fathom what he’s going through. It’s just unbelievable. I can’t even think of what it feels like,” he said.

The department is raising money to help Stewart’s family face the “unspeakable tragedy” through it’s charity, Ignite the Spirit.

jsheridan@chicagotribune.com