@timber2002 Sorry about your Dad. It is scary stuff but good for you for coming here and looking for answers.

If it were me, I would take @gently suggestions to get a clearer picture of internals with a PSMA/Pet Scan. If your Dad chooses radiation, come back here to talk about the type of radiation machine as some have real time, built in MRI and some don't, so side effects and quality of life can be more, or less, depending on that choice.

It also would not hurt to have a telehealth opinion from a center of excellence like Mayo. Doctors are dedicated but not infallible.