My experience, and thankfully very limited, has been that the bar bill from the night goes on the deceased's account but is paid for by the mess community - a tradition (IIRC) dating back to the WW2. As for cars/keys/phones etc I believe that all casualties are initially dealt with by the civ police until it is clear that there is no crime to answer (complicated the GR4 mid-air and the Puma at Catterick as I understand it) and what might be viewed as tampering with evidence (moving cars etc) would be frowned upon. Perhaps someone with more experience than me may be able to clarify.