CHICAGO (CBS) — A couple from the Hollywood Park neighborhood has sued their landlord, after a fire earlier this month left their 10-year-old son dead.

The fire started early in the morning of Nov. 9, on the back porch of a three-story courtyard building on the 5700 block of North Kimball Avenue.

Tahir Khan and Maria Tahir tried to get their family out, but the stairway was blocked by flames. They dropped their two youngest children out a window, to people outside the building, and then jumped to escape the flames.

Their oldest son, 10-year-old Ans Khan, didn’t make it out. Firefighters later found him dead inside.

“It was the family’s and the parents’ worst nightmare,” said their attorney, Tim Cavanagh. “They were able to successfully drop two of their children from three-and-a-half stories.”

Tahir and Maria were critically injured, and remained in intensive care on Wednesday. Both parents missed Ans’ funeral.

The two surviving children have been staying with their aunt, Safia Khan.

“It’s really hard for them to understand why this all happened, and why they lost their brother,” she said. “It’s really hard for us to go through all this.”

Safia Khan said her brother has been delirious since the fire, unable to grasp what happened, and is unaware his son died in the blaze.

“He’s on some other land. He talks all the time, like he sees murders. He sees somebody’s kidnapping his kids, and all that kind of stuff,” said Ans’ aunt, Safia Khan.

Cavanagh said Ans’ death is the result of negligence by the family’s landlord, Mihai Horga.

“There were not working smoke detectors in the building,” Cavanagh said. “There was no sprinkler system in that building, as well. This is a very big apartment building, housing multiple families, and why the city of Chicago doesn’t require sprinkler systems in the year 2014 is beyond me. This tragedy should be the last tragedy in the city of Chicago; where people have to die on high-level buildings, because there’s no sprinkler system.”

He said Horga has been cited for failure to provide working smoke detectors at least six times in the past, as well as other building code violations. Cavanagh said Horga has been hit with more than 100 violations in 10 years.

“This landlord did not care about his tenants. He didn’t care about this family,” he said.

CBS 2 reached the building owner, Mihai Horga, by phone. He insisted smoke detectors were working.

Under court order, the family’s own fire investigator will now examine all evidence collected by the fire department and insurance adjusters.