Riley Chapman-Wykes was the only one who could help when mum Megan collapsed at their home in Brixworth.
But instead of panicking, Riley ran straight to neighbour's house to raise the alarm and ring for an ambulance.
Mum Megan Wykes said: "I'm just amazed. He was so brave. I know adults who would just freeze in the same situation but he knew just what to do."
On July 26, Megan was home alone with Riley just hours after she had come out of hospital from another incident.
But suddenly, the 21-year-old suffered an epileptic fit and fell to the floor.
She said: "I can never really remember what happens moments before I collapse. But next thing I knew I came around and there was Riley with the neighbours and two paramedics. He was asking me if I was okay."
What Megan did not know was that she collapsed, Riley had sprung into action. He ran to a neighbours' house and called for help.
Riley said: "I was a bit sad that mummy was on the floor. I was a little bit frightened. I ran next door and told them."
The neighbour said: "He was just there in my doorway and said 'mum's on the floor'.
"He was ever so good and brave. He didn't cry and knew just what to do."
Megan was taken to hospital where she learned what had happened.
She said: "I'm so proud of him. I've spent time explaining what he should do but I've never known if he took it in.
"He was a little superhero. He knew just what to do."
Megan and grandad Kevin say they rest easier knowing they have a hero in the house to help her in the future.