Shei Shi Na Ge Ta

When his cheerful and optimistic younger brother passes away suddenly, Mu Siyang infiltrates his school to investigate the cause of his brother's death.

Shocking things come to light: his roommate was a friend with benefits; his rumored boyfriend wanted to kill him; all the customers at his part time job wanted him... What did my brother go through before he died?

(Source: Bilibili, translated)