I work in an open seating office and manage between two to six teams of folks, totaling about 35 in all. I'm in the military and my unit has a fairly high ops tempo -- this means that one month I may have 7 people from three teams working with me in the office and the next week I might have the full complement, then go down to two teams of perhaps six folks for three months. 

I'm experiencing an issue with a skip-level and I'm at my wits' end trying to obtain satisfactory behavior from him. He's been around the unit for two years or so and he's spent the entire time in a single work center (unusual for our unit). I moved to the work center a year ago, but I've known this man since he arrived at the unit. Despite the high travel rate for my unit, he's never deployed -- he took 18 months to pass our basic certification test (normal timeframe is 60 days, tops) and historically asking him to travel anywhere has led to doctor's appointments and tests that take up months of time and mysteriously aren't as urgent once he's taken off a trip. 

My issue is that delegating work to him somehow results in more work for me. I believe he thinks he's having a peer-to-peer discussion about the work, but my perception is that he's arguing about why he shouldn't do the work, why the work should be done by someone else, or sometimes that the work shouldn't be done at all. What's the right course of action to take in these situations to obtain compliance? Even simple tasks like 'make a list of the furniture in this room' result in his questioning what I mean by the word 'furniture' ("Does a light bulb count? What if it's not a working light bulb? Do you want to know how many fire extinguishers there are? Should I include the ceiling tiles?").  I have to assume he's not intentionally misunderstanding simple direction, but I also don't have time to hold his hand for every given task. He's been in the military for nearly 8 years now, so this level of helplessness isn't really excusable. His supervisor, my direct, is deployed and will be for another several months; so there's no chance to grow the supervisor by delegating this man's performance problems to him.

This man usually comes to me with questions, but if I'm unavailable he'll ask anyone in the work center. Normally I'd encourage this but I've walked in on too many tense discussions where he's oblivious to the effect his behavior has on whichever team members are present. Today he dragged all four members of a team that were in the office into an argument about what the word 'nothing' meant in the context of a report that he had read. His position that 'nothing' could mean 'something' under certain circumstances was entirely beside the point of the question he had originally wanted an answer to, which was "If the file says 'nothing to report' should I continue to work on it or move to a file that has something in it to report"? His words were loud enough that no other work could be carried on in the open workspace while he was talking, but his posture wasn't aggressive -- it appeared to me that he truly thought it was a discussion, not an argument. I intervened, removed the task from him, gave him very specific instructions about what file to work on next, and gave him the name of the only person he should discuss any questions he had with. I informed him that this was not a discussion, he did not get to pick which file to work on, and I let him know that I wanted him to work on this new file in another room (I had to tell him which room). It always seems right in the moment to take his focus off the others in the work center, since I appear to be the only one willing to stop him when he gets going (might be a rank thing), but it means that I don't get my work done because I have to stop and re-focus him a few times a day.

He came back to me later and told me that he wanted to talk to me about my behavior and asked for five minutes of my time. I didn't have it to give right then but I scheduled some with him. This also has happened before -- when I disrupt an argument he's having he comes to me and expresses that he feels maltreated. I attempt to explain his behavior ('when you speak loudly enough that no-one can hold a phone call, it disrupts the work center'), ask for him to change, and generally stick to my behavior guns. He then sulks for a day or two (doesn't make eye contact with me, doesn't respond to greetings, slams things around the office) and eventually gets over it unless I call him on the sulking behavior, which makes it last longer. Am I doing this incorrectly, somehow?

The worst part from my perspective is that he's leaving the military in about six months: I can't fire him; I can't move him to another office; I can't get him to do work without watching him like a hawk; and he disrupts folks who have to work near him. Is there a way to protect the other 34 folks I'm responsible for from this man's need to be the center of attention without creating an environment that's harmful to the team as a whole? If I could get away with making him sit silently at a chair in front of a turned off computer for eight hours a day for the next six months, I would. Unfortunately, I need the desk space for someone else to be productive at. This guy is literally a byword throughout our unit for 'something that looks like it should work...but doesn't' and I don't know what to try. Thoughts?