Hi! My cat is a 15 year old indoor house cat, and he's started having some trouble recently.

He walks unsteady, sometimes he stops and almost falls over. If you set him down he can't stand up right, he falls over. He can't jump, and I've seen him roll off the couch and not land on his feet. When he walks, I think he's clawing at the floor to maintain a grip. He eats normally, but seems to maybe be losing weight. And now, he's started leaning to one side whenever he's sitting or lying down. If he's not lying on his side, he's always leaning (to the left, if that matters). He has this weird habit of turning his head from side to side like he's smelling everything constantly when he's not sleeping/trying to sleep.

We took him to a vet a while ago, where they couldn't definitively tell us anything without charging us over $5,000 on medical tests, and put him on steroids. The steroids seemed to work for a while, but we can't give them to him daily, the prescription said for a few weeks, then slowly wean off. Which we did, and now he's just as bad if not worse. He also seems to be going blind (the vet said he was).

Any idea what's wrong? I saw sensory ataxia and that sounds kind of like it, but not definitively. Any other ideas?

He may have had a stroke or some other unfixable "neurological accident." Is it any kindness to continue to watch him struggle? Fifteen is a good age for a cat to have reached.

What the heck kind of testing would cost $5,000?
Did they do bloodwork, specifically a thyroid test and looking at kidney levels?