Un-Bun needs a CT scan

I'm AJ, proud bunnymom to Un-Bun (short for Unnamed Bunny cause I couldn't find any other name that would stick to him).

Please help me save my rabbit. He's a very sweet boy, only 4 years old, very kissy and he's trying so hard to keep going. He stopped eating hay about a month ago and has slowly been dropping other edibles off his diet, though so far with creative forgaing I've been able to keep his weight up (for now). We tried a course of antibiotics in case it was just a sinus infection but of course it's not helping as much as we hoped it would and he's slowly declining, as more and more food items become unappealing to him. I've already had him in to the vet's three times, plus weekly weigh-ins, and they can't find anything wrong inside his mouth that's not a symptom of something else, and it's been a rollercoaster ride of hopes versus reality.

My income is limited, and it's looking like the current choices are getting him in for the imaging (which will involve a few hours' drive to another city and sedating him, which comes with its own risks), or euthanasia. Depending on what they find, it may still come to that, but I want to be sure when I make the call that it's what's best for him. I hate the idea of euthanizing him for something that's easily treated, if only we knew what it was.

Funds will go to paying his vet bills (already $600+) and if I can get him in for the CT scan it will go to that and any treatment required. If not, well.... all pet owners know the way things can end, and even that costs money too.

Thank you for any help.