It’s a Hazbin Hotel fanfic by @whimsywillowwrites. The little girl is Imogen, and the boy is her anxious friend Oliver. A couple years ago, Alastor and Imogen made a deal that in exchange for her soul, Alastor has to come celebrate her birthday with her every year until she turns 18. Through this and a magic radio which allows Imogen to contact Alastor in hell, they've become very close. It's almost as if Imogen is Alastor's honorary child, but if you point that out he'll kill you. Alastor did not tell Imogen anything about what happened (because Alastor), however... Imogen is psychic, specifically “clairsentient”. So it’s hard to really keep anything from her 😂. The TV hatred is more of a subconcious thing.