I wish I had some knowledge about
such advanced PCa so that I could offer more than my sympathy and strong wishes for some good news for your father and yourself. He's lucky to have you.
I found this article on Lutetium PSMA therapy for men with PCa. Probably you've seen it already, but in case not:/www.ncbi.nlm.nih.gov/pmc/articles/PMC5355374/
Age 60 at dx
Dx July 2017 after biopsy G8 (4+4), 5/13 cores, bone scan clear
RARP Aug 11, 2017 (Dr Patel)
Post surgery pathology: pT3a, tumor 30% of gland; EPE+, SV- and 3 lymph nodes clear
PSA 1/2016, 2.9; 4/2017, 7.2; 9/25/2017 (first post-RARP), 0.13; 10/10/2017, <0.05