i'm pretty sure i've completed the db questline (keep getting the go-kill-that-guy-quests).
i am "the listener", the only person the night mother speaks to but as i recall from oblivion (and i think they've told me in this game), the listeners job is to tell the other db members what to do/who to kill.

now the whole brotherhood seems to be just me and the talking corpse, she tells me who to kill and i do it then she says "now kill this guy" and so on. the other members just sit on a chair in our sanctuary, watching the wall. meh..

Yeah, that's pretty much it. I enjoyed the hell out of the DB quests but after you're done with the main DB quests, it just gets very boring. At least let us delegate the contract if we don't feel like doing one specific contract. Maybe I will feel like doing the next one and choose to do that one myself.