@bear14: I agree with @gently. I had the MRIdian as well, with 5 treatments. It has real time MRI so what they can see in real time, gets treated. Elekta is another machine with similar capabilities. Generally, the whole prostate gets treated plus a “margin” that can expose your healthy tissue. You want Jeff to protect his healthy tissue and use a machine that has smaller margins, 2 mm for the MRIdian vs 3-5 mm with other machines. Healthy tissue exposure affects side effects.

Multiple opinions outside your current institution at a center of excellence is also important and spaceoar, if he gets radiation.

Everybody is different in their reactions to ADT as you can read on this site. My brother had nasty side effects but was not someone who exercised, as you said Jeff does and anecdotally, that seems to help.

It is great that he has your active support. Keep coming back.