Ryouta wa Otouto wo Koroshita

When their mother dies, junior high school student Ryouta takes care of his toddler brother Chika and their home. Overwhelmed by all the work, he begins neglecting himself. Without any time to himself, Ryouta comes to resent his little brother and soon the resentment turns into murderous thoughts. Little by little the pressures of childrearing make Ryouta lose his mind. But is Ryouta truly the issue? Or…

(Source: MANGA Plus)

Note: Includes one extra chapter.