Capt. Joe Stanton said the boys were playing unsupervised at a Texas City apartment Thursday when the 7-year-old found a handgun and it discharged. The 8-year-old was shot in the left cheek.
Stanton said Friday morning that the older boy was out of surgery and in the intensive care unit at a Houston hospital.
Police say there were no adults in the apartment when they arrived. Stanton says a boyfriend of the victim's mother may have been responsible for supervising the children.
Texas Child Protective Services is reviewing the incident.