Hi--I'm a dad with a lot of the same stuff going on as your dad. I had TURP about three weeks ago myself for a blocked urethra after my radiotherapy, and I've been on Apalutamide for 10 months now. I also take Dutasteride. My Gleason score was 4+3=7 when I was diagnosed in January 2022.
Sadly, I haven't experienced the loss of appetite as your father has and so am as fat as ever (haha), but I can defo relate to the rest of his experience. Depression and fatigue have characterized my journey with PC treatment. I had to take a leave of absence from my job because I could not sleep and was so tired all the time.
There is hope, my friend: 10 months in, I am looking at the end of my Apalutamide and Dutasteride therapy in two more months (actually 7 weeks). I have also felt much better after the TURP surgery because I do not need a catheter and can urinate normally. Additionally, because of the Apalutamide and Dutasteride, my PSA is .001 and 'undetectable.'
What I'm trying to say is that just four months ago was the darkest time of my life. Radiotherapy, Apalutamide, Dutasteride, catheterization, extreme fatigue, depression, no working. Now, I'm feeling better, radiotherapy's done, I can see the finish line with Apalutamide and Dutasteride, the TURP has helped immensely, and I've begun exercising again. I am not out of the woods, but I am not deep in the middle of them anymore, either.
There's a phrase I say to myself a lot these days: "The only way out is through."
Best of luck to your father and to you. We can do this. We can definitely do this.