It doesn't seem to me that they would deny you.
And I don't think you should be worried about the officers having a bad day, even if they do, they still have certain standards to maintain and rules to follow. yes they have the choice to deny you, but they need to have a really valid reason, they wont deny you for something that's not legit. your husband shouldn't worry about that!!
usually the police certificates and medical redos are asked for after the relationship evidence is already looked at. so if they didn't have enough evidence they would have asked for it before ur police checks or at the same time as them.
I think you will get approved, you just have to be patient.
I know a few people who have taken close to a year to process, because of silly delays, and still get approved, just their case takes a bit longer.
tell your husband to just be patient, his time is coming, they just seem to be working a bit slower than usual lately.