He said that even after he couldn't get an erection, he would still imagine killing and having sex with people because it made him feel alive.

"I know exactly what you mean. You know what's better? When they're old and lonely and can't fight back or don't have anyone who'll believe them. I once shoved a kitchen knife in a 90 year old's ass cause he wouldn't stop whining when I fucked him. He loosened up real good after that."

Worst case scenario, you creeped out an old man with a bad sense of humor. Best case scenario, for the last days of his life a twisted psycho murderer who's been hiding his true nature behind good deeds gets to feel a tinge of fear whenever he's not sure he locked his door.