rolling rat etc

Question
I have 6 week old male that started with a head tilt. I took him to the vet and they put him on 2 antibiotics - doxycycline & batryl. He didn't respond. He started rolling and now he can't see out of the eye that he's always laying on and I can see that it is changing colors. I know that I can take him to the vet again but I also figure it's not a bacterial ear infection like we hoped. The vet is rather costly for an x-ray to tell me that his middle ear is involved. They've told me that there's nothing else they will do unless they do the x-ray. Is there anything you can tell me that will help me make his life as comfortable as I can make it? I just want to make sure I'm not being completely negligent here. I know there are plenty of people who would scream at me at balking at $130 for an x-ray and I have thought about adopting him out to someone willing to spend hundreds of dollars on diagnostics. I've also called other vets that are quite a bit away but not as costly and I may bring him in to one of them instead. Thanks in advance.

Answer
 If he is not responding to antibiotics it may be something more serious such as a neurological problem or a brain tumor or head injury that has caused the problem.  Since he is so young it may be something genetic; I've had that happen to a rat or two for no apparent reason and they eventually passed on as no treatment would stop it.  It sounds like your rat is probably not going to make it, I'm afraid, so don't feel bad about not wanting to spend the money trying to fix it.  If it isn't an ear infection and antibiotics aren't helping there really is nothing that can be done.  You may want to consider having him humanely euthanized if his quality of life is such that he cannot eat, drink, or walk properly.  I do hope he gets better, but usually once a rat gets to this point there isn't a lot that can be done.