Authorities also released video of the two suspects from inside a different Subway restaurant.
The victim is 18-year-old Javier Flores, described by his friends as someone who was working to help his family. Both Flores and his mother worked at the Subway on the 3900 block of Broadway in southeast Houston.
His father, Carlos Vasquez, told Eyewitness News that Javier was always there for his family.
"Active, he liked to participate in theater class, he always backed up his family and friends," Vasquez said.
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Flores' friends are not surprised that he did everything possible to save his mother.
"He had my back. He had his friends' back, his family's back, like always. He had someone's back if you had his back," Helizander Rodriguez said.
Patrol officers were called to the Subway around 8pm Wednesday, where they found Flores with a gunshot wound to the neck.
VIDEO: Houston Police Department Detective David Crowder addresses media after shooting
Police say the two suspects walked into the restaurant and pointed the gun at the victim's mother. Flores pushed his mother aside as the two would-be robbers pulled a gun and shot Flores. No customers were in the restaurant at the time of the shooting.
Rodriguez was with Flores' father as the family was rushed to Subway after the shooting.
"It looked bad. For a friend to look at him like that, it was bad," Rodriguez said.
Flores was taken to a local hospital for medical treatment, where he later died.
Endy Herrera has known Flores since middle school.
"I was kind of heartbroken, and I kind of feel like shedding some tears because I have been knowing him for a while and how he took a bullet for his mom, I would call him my hero for doing that," Herrera said.
Investigators are looking for two males who fled in a "tan, foreign, small car." Another robbery occurred at a nearby Subway restaurant, and police are looking into whether the two may be related.
The suspects are both described as black males, one is 18 to 20 years old about 5-7 with no facial hair. He wore a dark blue hoodie and black pants.
The other is described as being in his mid teens, possibly 17 years old. He had on a light blue colored hoodie and black pants.
If you're looking to help the family, you can donate to their GoFundMe account.
Anyone with information is asked to contact the Houston Police Department or Crime Stoppers at 713-222-TIPS. A reward of up to $30,000 is being offered after a $25,000 gift from a concerned citizen.