You’ve probably seen clips of dogs stepping in to protect their humans from danger, sensing trouble before it hits. But in a recent incident, a dog turned hero not for a person, but for his fellow four-legged friend. In Milford, Connecticut, United States, a French bulldog named Yogi, who suffers from severe epilepsy, was home alone with his younger brother Reggie, a 16-month-old boxer. Their owner, Sarah McArdle Strilka, wasn’t home when Yogi suddenly had a seizure. But Reggie sprang into action. Surveillance footage captured Reggie's instinctive response. Despite having only seen one seizure before, he rushed to Yogi’s side – nudging him, pacing around, and keeping him upright to prevent choking or aspiration. For nearly three hours, Reggie stayed by his brother’s side, offering support and comfort until Strilka returned. “As soon as Yogi started seizing when I wasn’t home, Reggie jumped into action,” she told Storyful. “If it wasn’t for Reggie, Yogi would not be alive today.” The touching video, shared by multiple Instagram accounts including @sarahmcardlestrilka, quickly went viral. You can watch it here: View this post on Instagram A post shared by CBS News (@cbsnews) Many users responded to the video. One user commented, “Animal nature is incredible. Empathy is engrained. We sure do have a lot to learn from them.” Another user wrote, “The way he looked around for his humans to help and realizing that no one was there so it was up to him to save his buddy.” A third person asked, “How do you leave your dog alone that has epilepsy?” A fourth user said, “Reggie is now a certified support dog for Yogi. Their natural instincts sense the smell of the dog. It’s just like they are trained for humans for these same reasons.”