Stephen Archer, 51, of Victoria Street, Openshaw, Manchester, was convicted on Thursday at Manchester Crown Court of murdering his sister Julie, 49.
Ms Archer suffered 95% burns in the attack at her home on Surbiton Road, Newton Heath, in February 2016, the court was told.
Archer was told he must serve a minimum of 27 years.
The jury heard Archer had falsely accused her of murdering their father and uncle and doctoring a will to disinherit him.
The court heard Julie was left with "horror movie" injuries after Archer doused her with flammable liquid and set light to the vapours as she sat on a sofa.
Ms Archer's 19-year-old daughter, Quibilah Archer-Cunningham, escaped with minor injuries after jumping from an upstairs window of the house. The family dog died in the blaze.
Archer was cleared of arson with intent to endanger the life of his niece.
A man who set his sister on fire using a "petrol cocktail" has been jailed for life.