While the overall event is corroborated, the specific detail about the younger brother arming himself with a knife is not explicitly detailed in the snippets from Sentinel Colorado or Denver7. The provided web search results for 'Younger' are irrelevant (TV show). Only the source 'Police: Aurora man fatally shoots brother after argument' contains the narrative of the argument, though the snippet provided for claim 2 is actually irrelevant TV show data. However, looking at the evidence for claim 4, the same source mentions the sequence of events. Since only one news source provides this specific detail in the provided evidence, it is marked as single_source.

The detail that the older brother armed himself with a gun and fired following the knife incident is found in the snippet for 'Police: Aurora man fatally shoots brother after argument'. Other sources confirm the shooting but not the specific sequence of the knife first. Other search results provided are irrelevant (3D printed guns, school incidents, and a different case in Banda).