Sending lots of good wishes your way. It's so hard emotionally to see them going downhill. And I know it can be hard dealing with vets sometimes. I've been lucky enough to find one who doesn't seem to mind that I come in with a stack of research and a lot of suggestions- I think it helps that a couple of times, I've been right about a problem that he couldn't initially see (I once insisted that Sundae have her teeth examined under anesthesia when an awake exam didn't show a problem because I had seen her pulling at her lips in a way that I associate with dental issues- turns out she had a molar spur that couldn't be seen until she was completely under and her mouth cleaned of all food debris. The vet called me personally to tell me I was right, and since then we have a really great history of working as a team!) It sucks that some vets see owner suggestions as an obstacle rather than as an asset. Since my vet figured out that I am observant and don't mind getting my hands dirty, he's actually taught me lots of stuff, from how to mix antibiotics by weight to how to clean abscesses really thoroughly and has even given me some free meds/tools over the years to help me out. I do see an exotics vet (they do dogs and cats as well), but they have plenty of rabbits and rodents as patients as well. I'm also somewhat picky about who I see- there are three vets in the practice but one has more guinea pig experience and he was the only guy I would let handle Sundae's teeth when she was having dental abscess (luckily the other vets are fine with that, as he does most of the rabbit/piggie teeth in the practice so they tend to schedule dentals with him anyhow.)
Just read this thread. Very sorry to hear that the beautiful Casran is under the weather. Sending lots of healing vibes and wheeks, and praying for his speedy recovery. 
)
