If his PSA is 1 and he is peeing like a racehorse, then please sleep soundly tonight.
It sounds like he is being well looked after by his medical staff and he has a lovely wife like you to be by his side.
Prostate cancer grows slowly but so far there is no indication of it.

My father had prostate cancer in his early 60s and lived until 89.... a long and happy life
WITH prostate cancer.

Please go out for dinner, order wine and clink your glasses to good health.
My best, D.