Dandridge is the most discreet vampire

Think about it. He doesn't let anyone in on the fact that Amy is a dead ringer for his long ago lover. He talks with Charley's mom about trivial stuff and not once snitches on him, as he prefers to deal with the snoop like a man. Before turning Evil Ed, he hints to him on knowing who he is but no need to discuss it openly. That takes understanding and Evil trusts him for that. Dandridge mentions his lover in passing to Amy when she spots the old painting without going in detail. He also doesn't talk about his life or about Billy Cole, his roommate and servant; in fact, Dandridge doesn't even mention his servant by name at all. That's real confidence and some real discretion.