Mukhtyar Ali, who used to run an air-conditioner repairing shop, was stabbed in the chest with a pair of scissors by Dilshad, 30, at his house in central Delhi's Chandni Mahal area around 10.45 a.m., police said.
Police said Dilshad is absconding.
The two brother had a property dispute due to which the murder took place, police said.
Ali, who is survived by his wife and four children, died on way to hospital, police said.
Ali was the elder among three brothers. All the brothers live in the same building in Chandni Mahal area. Ali lived on the third floor and Dilshad on the second floor of the building, police said.