His relationship with his father

I went straight to youtube after watching the movie, looking for an actual footage with Dahmer. I did that because when I first saw his picture, decades ago,I thought he was more of a redneck type. I watched briefly an interview, with him and his father, and Dahmer seemed educated and articulate. What striked me was the way his father looked at him when he started answering the journalist's questions. I realised he still loved his son wich made me think "ok, at what point are you able to draw the line?".
I mean, if someone really, really close would do such things. Quite chilling, actually. Dahmer was very manipulative in his own dorky, introvert way. Probably is a common trait for psychopaths or whatever he was.

bonus:
That scene where his mother just left and he gest out of his room, dressed like a normal teen back then, made me think of Tom Cruise in Risky Business. Almost expected Renner to do the dance.