Rat update: The little guy is seriously ill, but it comes and goes. Mostly he's fine, but the spaz attacks are getting more frequent. As a general rule, if you can't immediately tell what's wrong with the rat by looking at him, it's probably not fixable. I haven't the foggiest idea what's actually going on in there. I assume I'll lose him soon.
He's getting my standard palliative care, i.e., whatever he wants, mostly drugs. Rats do have enough of a logic processor to make the connection between medication and effects. There are a couple different antibiotics that vets use for treating myco, for instance; the clindamycin is mostly well-tolerated, but Baytril makes them feel really bleargh. Rats who've had clindamycin only will shove each other for the stuff, as it's in flavored glycerin, but they'll only take the Baytril once before they start clamping their mouths shut and wrenching their heads away. The broken rat will take his baby Tylenol and Benadryl even when he won't eat or drink, so I assume something they do is making him feel better, even if it's only the sedation making him less frantic.
(The easy way to get a rat to take medication he doesn't like, by the way, is to smear it into the fur on his belly, and then wet your hands and pet the rest of him vigorously in all directions. He'll shoot you a death glare and sulk a lot as he scuttles off to fix his fur, but it's infinitely less traumatic than getting pinned down and having a syringe jammed in his mouth. Just be sure that if you have more than one, you keep an eye on them until every rat's finished washing himself, in case someone gets over-enthusiastic and tries to groom everyone's dose off them.)
In between attacks, he's not very spritely, but he climbs about in the cage all right, and vacuums up maple oatmeal like it's going out of style. He's getting Tylenol every 4-6 hours; diphenhydramine has a very wide therapeutic window and isn't likely to be toxic in amounts he can lick off my fingertips -- not that it would matter much if it were -- so he can have as much as he likes. He gets to sleep in a towel in my lap if the other two rats annoy him by trying to "help".
I'm debating the merits of taking him into a vet and just ending things quickly. I have absolutely no way to pay for this. The MSPCA is usually very nice about giving services as cheaply as possible, but I'm not entirely sure I have T fare at the moment -- there's little or no modeling work over the holidays, as the 'togs are busy with people who pay them for Christmas photos, and that's normally how I'd make ends meet. The rat may not last long enough for it to matter. He's calm and washing his face right now, so I think he'll survive long enough for me to run errands today, but how long exactly, I couldn't say.