Yes. This event occurs as a significant plot development and has a major impact on the story. Mikasa's action is driven by complex emotions and circumstances within the narrative.
In the Naruto canon, Naruto would never kill his mom. However, in some extremely dark and non - canonical fanfictions, the author might create such a scenario for shock value. But this goes completely against the spirit of the original series. Naruto is a story about love, friendship and growth, and such a plot is a very perverted deviation from it.
Well, there could be various reasons. Maybe there was a deep-seated family conflict that escalated beyond control, or Jeffrey might have been influenced by external factors like drugs or a traumatic event.
It could be that the Moore was mentally unstable or influenced by external factors that led him to commit such a horrifying act. There might have been financial problems, jealousy, or a history of abuse that culminated in this tragic event.