Lopez's children range in age from 2 to 16. They joined police Tuesday to announce the reward.
Lopez worked two jobs, one at the Hoagies and Wings restaurant on Ventura Boulevard in Sherman Oaks. He was fatally shot there on June 29 after a fight broke out among customers and Lopez chased five men out of the restaurant.
According to police, it was around 11 p.m. when two men, whom detectives are calling persons of interest, walked into the restaurant to order food. Surveillance pictures provided by the LAPD were taken from a nearby restaurant that was closing for the night.
Detectives say the men were part of a group of five men who ordered some food. The group than complained about the time it took to prepare their order.
That's when Lopez and the men got into an argument. Lopez, according to police, chased the men out the door with a chair. Police say that's when one of the men pulled out a gun and shot Lopez.
The reward announcement was made at the restaurant Tuesday. Lopez's family asked any witnesses to come forward.
"We lost our dad and we can't replace him because he's the only one," said Raul's son, Melesio Lopez. "We feel really sad and we can't really express it."
"Raul Lopez should be here today," said L.A. City Councilman Tom LaBonge. "He should be holding these children. He should be part of their lives. But he was taken away by someone who we could now prosecute and bring to justice."
Lopez's family members and Hoagies and Wings set up a memorial fund for Lopez. The restaurant said it will provide donation boxes at the Sherman Oaks (14552 Ventura Blvd.) and La Cienega Boulevard (1544 S. La Cienega Blvd.) locations.
The restaurant will also be donating 10 percent of all online orders placed on its website from the Sherman Oaks location through July to Lopez's family.
Investigators are still searching for Lopez's killer. The gunman was described as a black man in his late 20s or early 30s with a skinny build and short hair, about 5 feet 6 inches to 6 feet tall.
If you have any information that can help authorities, you're urged to call LAPD Van Nuys Homicide detectives at (818) 374-9500 or (877) LAPD-24-7.