Given that he's been (at the very least) missing for several days, at this point even the best-case scenario isn't very good.
Anyway, thanks for all the comments; I won't be replying to most, but that doesn't mean I don't appreciate them. I just don't have much to say, and saying anything about it is difficult right now.
I did go to see a movie at Mike's place tonight; I didn't actually tell anyone what had happened except Mike (and I did that after everyone else had left -- I though if he was going to help look after the cat, he should at least know why. I almost didn't do that much). Because, really, I didn't want anyone to know, because first I didn't want to put a pall over the precedings, and second, well... I know everyone would want to be sympathetic and help if they could, but there's just nothing anyone can do, and the eggshells that everyone would be walking are good for nothing but bloody feet. So, I suppose this will be trickling through the circles of friends I have that don't read LJ. So be it.
There's worse to come, of course, dealing with insurance and who knows what else. But those are problems for another day.