Yuzuki-san Chi no Yon Kyodai.

Hayato, the eldest son of the Yuzuki family, is left to take care of his three younger brothers by himself after his parents suddenly passed away two years ago. He struggles with both work and housework but is often left alone to deal with the burden. One day, when he comes home from work, he is informed by Mikoto that Minato and Gakuto have not returned home yet. Hayato and Mikoto rush to find them.
In fact, Minato was always dissatisfied with being treated more like a child than Mikoto, who was in the same grade as him. At that time, he learns that his younger brother Gakuto wants to go to a place where he has fond memories of his parents, so he takes Gakuto with him to prove that he, too, can do things like an older brother. However, Minato gets separated from Gakuto in the crowd... Will the four brothers be able to meet safely again?
(Source: Japanese = NHK || Translation = MDL)
~~ Adapted from the manga "Yuzuki-san Chi no Yon Kyodai." (柚木さんちの四兄弟。) by Fujisawa Shizuki (藤沢志月).