Is there any point at all for doing the last missions for the Dark Brother Hood? The last mission is repeating but does it ever end or is it just a continuous source of gold that you can farm over and over again with ease? To tell the truth I just want it gone from the quest bar because the night mother is continuing to nag me until I do the mission. And even then it irritates me as it becomes the next quest available immediately.
I had limited success with the console command:
On one computer where I used it the quest came back right away. On another it failed, then I got it to work (I think) with careful timing: first I completed the quest, then I entered "resetquest DBrecurring" quickly in the console before it had a chance to repeat. I haven't test extensively, so I can't swear timing was the fix, but that worked for me.
For a less touchy solution, PC users can download a mod from the Skyrim Nexus that disables the quest.
I will never be gone, its another one of those radiant quests that are randomly generated. And since the quest targets are always created at the start of the quest, you can't get around it by killing every NPC in the game either.
If you are on the PC, however, you can get rid of the quest with this console command: