Henry Allison, 71, died at Loyola University Medical Center in Maywood. Four-month old Lylian Robinson and 4-year old Calvin Robinson were listed in critical condition at Loyola.
There was no word yet on what started the fire.
Brookfield Police Chief Steven Stelter said Allison called for assistance. However, smoke and fire was belching from the building when firefighters arrived.
Police say the three were the only ones in the home at the time of the blaze. A 10-year-old brother was down the street at a library and the children's parents were away.
The Associated Press contributed to this report.