ziggydeep, some prostate cancers tumors don't produce PSA; some prostate nodules are not cancer.

The next test is usually a PET/CT That will tell you if the nodule is using a lot of sugar, which would increase the suspicion of cancer. I assume your spouse will have a biopsy no matter the PET/CT results.

The biopsy will confirm or rule/out cancer. If it is cancer, the biopsy will yield a gleason score, giving you an idea of the tumor type and a choice of watch and wait or treatment. https://www.pcf.org/about-prostate-cancer/diagnosis-staging-prostate-cancer/gleason-score-isup-grade/
The biopsy sample can be sent for somatic testing--testing of the mutations specific to this tumor.
When he has a biopsy, make the request for Decipher Testing to be sure they retrive a large enough sample.

Meanwhile, ask for a PSE serum test. It's fairly new and said to be 94% accurate. But it isn't commonly ordered.
https://www.94percent.com/
https://www.veracyte.com/decipher-prostate/
Treatment for prostate cancer has gotten so good that they tell all of us that you have to die of something else.
Best wishes