Two deathclaws jumped me and Boone. And I'm pinned on top of a tractor or something, where they can't get me, and have been unloading on them for like 5 minutes now. Boone still hasn't gotten back up from being knocked unconscious. What's wrong? Is he dead?

Pretty sure they won't get back up until the encounter is cleared.
Unless you're playing hardcoe. Then they'll never get back up.