I think the red hair guy a.k.a the MCs “aunt” rescued and adopted the blue hair guy a.k.a the mad dog. He was called “father” because he technically raised the blue-haired guy like a son, but then the mad dog developed feelings for him and is now being obsessively possessive. That is why the red-haired guy says he should have left the mad dog to die (and not the MC) because he seem to dislike what the mad dog is doing to him now. I dunno. I thought he liked him in the previous chapter, but when the next chapter came where they had sex, he seem to dislike it.
I think the red hair guy a.k.a the MCs “aunt” rescued and adopted the blue hair guy a.k.a the mad dog. He was called “father” because he technically raised the blue-haired guy like a son, but then the mad dog developed feelings for him and is now being obsessively possessive. That is why the red-haired guy says he should have left the mad dog to die (and not the MC) because he seem to dislike what the mad dog is doing to him now. I dunno. I thought he liked him in the previous chapter, but when the next chapter came where they had sex, he seem to dislike it.