Did they ever explain why these patients were in Greenland? Were they experimenting on them? Were all the VA hospitals in the US filled? I think this would have been a better movie without the X-Files wannabee aspect, but I guess its based on a book and so has to follow that to a certain degree.
From what I got, they were the men under the colonel and I guess a mission went wrong. The letters to the families said they died in battle and their bodies were irretrievable, probably b/c there would have been questions otherwise. They were kept there until they died. Or maybe it was something completely different, but that is what I got out of it.
"That's something you'll never hear from me, Capt. Butler, as long as you live"
I got the impression that it was a foregone conclusion that this base would be completely obliterated at the time of the last patient's demise; this, to me, explained the attitude of the Commander, who allows increasingly lax discipline.