@sumith
I am unsure why you are asking this. You’ve already said he won’t respond to Darolutamide Because he has already Failed Enzalutamide.

In that case going to Darolutamide Is probably not going work at all, and a low-dose of it won’t help.

I know people in their 80s that are using Darolutamide As their only drug and it works great for them. So the safety of the drug is not a problem, the Efficacy of the drug is what Is questioned whether it is a full dose or a half dose.

The two drugs are too similar.

This is a case where you could try BAT. Giving testosterone injections for a few months to see if it will reset the ability for a lutamide drug to work. It works for about 50% of people. The injections of testosterone would definitely make him feel better. The question is, will it raise his PSA too quickly and defeat the purpose.

There are a couple of BAT articles. The second one has a bunch of stuff about treatment of advanced prostate cancer as well.
https://pmc.ncbi.nlm.nih.gov/articles/PMC9313844/
https://online.flippingbook.com/view/150884930/2-3/