There is quite a bit of discussion about so-called intermittent ADT.
You might google the subject "intermittent ADT"searching it thru AI on Google

Your husband might also wish to consider joining this clinical trial headed by Dr Ravi Madan SENIOR Clinician at NIH/NCI. I'm in it and it's still recruiting.
It's at the NIH in Bethesda, MD but they cover transportation costs. Your husband's doctor would still be the lead dog on the sled and would get all the test and imaging results if he wishes, as would your husband.

Here's the info

Prospective Monitoring of Subjects With Biochemically Recurrent Prostate Cancer Using 18FDCFPyL

ClinicalTrials.gov ID NCT05588128

Sponsor National Cancer Institute (NCI)

Information provided by National Institutes of Health Clinical Center (CC) (National Cancer Institute

Google this for his recent update
Asco 2025: Prospective Monitoring of PSMA–positive Biochemically Recurrent Prostate Cancer: Preliminary Data from 6-Month PSMA Follow-Up