So, if you think the quest is broken and you're going through the console commands, I assume that you found the quest via player.showquesttargets or in the CK. The process I use and have found elsewhere (Not Steam): 1. showquesttargets. 2. showqueststages [questid] or [name]; 3. setstage [quest id] [no.] (which is the first number showing zero from showqueststages. Voila (as the French say it, totally ignoring voici as if it didn't exist).
And if you're sure you have done the above currectly -- Are you sure? Are you sure? are You sure? -- Find the next quest and type in startquest [name or id]. Usually, if you have done the above correctly, the quest shows complete on the quest screen.