Hi, Faithlilly. Sorry to hear about Robbie.
Was Robbie's nose ever irrigated? Sometimes it is
just something stuck up there.
As for xrays, our vets have had some pretty good luck taking xrays of our dogs using only a fairly light sedation--not sure if this would work in Robbie's case, but if it's possible, it would be a lot less risky for your old gent.