Whats is next after enzalutamide stops working

Hi.

Hubby was diagnosed in Jan 17 with stage 4 spread to bones. Been on zoladex since. Dec 19 psa started doubling in a month and put on bicalutamide.  Jan 19 this did nothing, so put on enzalutamide. Apr 19 had to stop as not working either, and also damaging his liver. May 19 liver now fine. Back to oncologist July but not sure what to expect. He is being tested on the Triton 3 trial, but we know the chances of getting on this is slim, as you need to have the Brac gene. He doesn't want chemo. Any ideas on what they can offer him. At present he is lucky and not in any pain. He keeps stating that he won't be here at Christmas, but what is his life expectancy,  and I know it's only a guess as everyone is different. Thanks