Video report by ITV News Midlands Reporter Ben Chapman
Anthony Nicholls suffered severe burns and smoke inhalation in the November 2 fire.
The 56-year-old did not regain consciousness after the Birmingham attack and died in hospital five days later.
Mr Nicholls' partner - a 50-year-old woman - suffered life-changing injuries and fractures to her legs after jumping from a first floor window in an attempt to escape the blaze.
Issuing an appeal for information following the "horrendous" attack, Fiona Nicholls, Mr Nicholls' daughter, said: "I just want to appeal to anyone that has any information about what's happened.
"It's horrendous what's happened to my dad. Words can't describe how me and my family are feeling."
"My dad made no enemies. He was hard-working, he was a funny man. I just want someone to come forward and give any information whatsoever."
Speaking appearing alongside Ms Nicholls, Detective Inspector Paul Joyce said police believe the fire started after the front door of the home in Birchtrees Drive in the Tile Cross area of the city was forced open and a large commercial-sized firework placed in the hallway of the property and set alight.
Previously police said the firework is thought to have contained around 200 tubes of explosives and would have taken around two minutes to fully discharge.
They continued that the home caught alight quickly and was gutted by the blaze.
Officers have yet to establish a motive for the arson attack.
Det Insp Joyce continued that he believed the couple were attacked by "a group of people who are local to the area...
"My understanding and my belief is that the answer lies within the local community and I would urge anybody that knows anything about this crime to come forward and tell us what's happened."
The £10,000 reward is on offer for information that leads to arrest and conviction of those responsible for the murder.
Anyone with information on the fire should contact West Midlands Police on 101 or Crimestoppers anonymously on 0800 555 111.