Good news. Don’t get hung up on what the exact PSA figure is. Mine was 4.6 two months after RT, 2.0 six months later, and bottomed out at 1.4 six months further on. My oncologist said at the start of my treatment that a nadir (minimum value) of 2 or less he’d consider a successful outcome. Your husband still has a prostate and is still producing PSA. What matter is how it changes between tests.
Best wishes,
Chris