Syed Sorafot Ali is believed to have suffered a heart attack after rushing from his home to his daughter's house in a block away when he heard about the blaze in Sunderland, north-east England.
His daughter Syeda Sahnaz Begum, her husband Abul Kalam Azad and their five children, aged five to 21, escaped the fire, which broke out at around 3:30 am (0330 GMT).
But four of the children are in hospital suffering from smoke inhalation and broken limbs sustained when they jumped from windows to escape.
Azad said: "My father-in-law collapsed and died because of this incident and I have no idea why anyone would want to do this. We are peaceful people living in Sunderland."
Chief Superintendent Dave Pryer, of the local Northumbria Police, said a brick had been thrown through the house's front window before a blaze started in the hall.
"At this stage, the incident is being treated as racially motivated," he said, adding that arson was suspected.

Copyright AFP (Agence France-Presse), 2006