@jeanadair123, Urethral stricture is mentioned as one of the side affects of radiation therapy according to Mayo Clinic's website - Urethral stricture
Symptoms & causes: https://www.mayoclinic.org/diseases-conditions/urethral-stricture/symptoms-causes/syc-20362330. There is also some information on advanced diagnostics and treatment at the Urethral stricture care at Mayo Clinic: https://www.mayoclinic.org/diseases-conditions/urethral-stricture/care-at-mayo-clinic/mac-20362386

@artscaping may have some more thoughts on what might help.

Has your husbands symptoms increased gradually since after the radiation treatments?