Willie seemed to be relatively comfortable last night (he wasn't crying, anyway), but with cats, you can never tell what's going on. He did seem to be stiff and in some pain when he tried to move, so needless to say, he didn't move much. Mary managed to force-feed him some a/d (for cats with a bad appetite), and he's had a couple of doses of doxycycline, but he's doesn't appear to be getting any better. I took him back to the vet this morning for observation and to await the results of the bone marrow test that was taken by the internal medicine doctor. Our vet wants to try him on prednisone to try and stir his appetite, but not until he hears what's going on with the bone marrow. So, all we can do is wait.
I've reconciled myself with the other option. I love him too much to prolong his misery.