Thanks again, everyone. Just got back from our 2nd vet visit of the week. They said that he has shown some improvement, but that it is still serious. He has put on 200g, rather than losing weight, so that's a definite good sign. I've also heard his raspy breathing less... But vet says there is still lots of fluid in his lungs. She actually used the word "pneumonia" which I guess the other vet was avoiding. It's a big scary word in general, but even moreso in rabbits... Luckily, when the infection was in his nose we had a swab done to see which antibiotics it is resistent to, so there's no guessing games there. Have to bring him in next Wednesday unless he begins to decline, in which case we'll have to rush him in.
He's still very happy and bright, eating and drinking lots, doing crazy binkies (Anyone know what these are? They're hilarious.) around the house, being his usual stroppy self at times... So I just have to hope the antibiotics continue to improve his condition. Today he received his anti-inflammatory injection, his antibiotics, and I've been given some other medicine that we can give him at home to help break up the mucus. Also going to put him in the steamy bathroom every time I have a bath or shower to help that along. Please keep your fingers crossed for my brave little man!