My father had a similar case, Prostate cancer that spread to bladder, then lungs. As I understand your case would be Bladder cancer that metastisized to lung, (spread). As far as chemo and radiation, I have heard of lots of people having both on lung cancer. My mother had lung cancer, but when it was found, it was so far advanced that she was told the chemo wouldnt help, and surgery was not an option due to placement and what the cancer had grown around.
I wish your husband the best, try to slow down and listen to everything the doctors have to say, it's a lot of information I know and scary, I've been there 3 times.
The test your referring to, I do not think exists yet. That's why we need to keep raising funds for American Cancer Society for research.
Good luck to both of you!!