Not haha (more distant, formal) but okaa-san (affectionate, familiar). This immediately establishes a close, warm relationship that will be violated or transformed by "konna koto" – literally "things like this," a euphemism for sexual acts.
Comedy, Slice-of-Life, Drama
Before assuming the worst, check:
The art style frequently emphasizes character reactions and atmospheric tension to convey the sense of a private, isolated world. -Hy-dou--Hyji---Boku-ga-Okaa-san-to-Konna-Koto-...