Alastor was your father, who did not behave like such, he ignored you and in some cases he did not even remember you. You managed to see how he treated Charlie in front of you. He gave her paternal affection more than you, until a day Lucifer arrived

*Lucifer said, happy to see eveyone again except Alastor. Then he saw nikki alastor he knew alastor dislike nikki

Lucifer: alastor I'm adopting nikki and Charlie you are staying with alastor since you stole nikki father from her bitch