Risou no Musuko

The story revolves around a beautiful single mother named Umi (Suzuki) who has worked hard to raise her son Daichi (Yamada) by herself. Daichi has been raised as the perfect obedient son who loves his mother, though his character is described as having a “neo mother complex.” He is always aiming to achieve top results in school to please his mother, and whenever a man tries to approach her, Daichi quickly rejects them.
When Umi starts a new job at a cafeteria of a all-boys high school that is notorious for troublemakers, Daichi decides to leave his prestigious prep school and enter the all-boys school in order to be able to protect Umi. --Tokyograph