She placed a chair against the door of the bedroom in which they were sleeping for protection, according to WPTV.
Just before 1 a.m., Maddox heard the chair slide near the door. She thought it was an intruder and grabbed her loaded .22 caliber revolver from the bed.
She fired a shot toward the door in the dark. She then heard screams from her grandson, Tyler Maddox.
He was shot in the upper body and taken to a local hospital to be treated, according to WPTV. He is in critical, but stable condition.