Robert Price, 76, was declared dead shortly before 6 pm on July 27 at his home in Oval Road North, Dagenham.
Nathan Otitodilchukwu, 18, previously from Crow Lane in Romford, declared himself guilty of involuntary homicide.
A 16 -year maintenance, which cannot be identified due to its age, also admitted Manslauhter.
It is not said that otitodilchukwu has thrown the fireworks, but it is said that it was part of the group that began the fire, the old Bailey was told in a previous audience.
The couple had to be sentenced on Friday, April 25, but the audience was withdrawn to May.
The Forensic Court of East London heard previously that “it was seen that a group of men approached the direction of the house of the departure and threw an illuminated flare to the property.”
There was a fire, said the Forensic Graeme Irvine, and Price’s death was declared by paramedics of the London ambulance service.
Since then, a forensic autopsy on July 29 has given the cause of death of Price as “inhalation of fire fumes and burns.”