Hi there....I can't give you timelines understandably. Gleason score 4 + 5 means that the most common cancer seen is a Gleason 4 and the second most common is a 5. From my own husband's prostate journey, Gleason 4 is intermediately growing and Gleason 5 is fast growing so this makes sense that there would be perineural invasion which means the cancer is seen along a nerve within the prostate.
His urologist should be referring your father for treatment. How old is he if I may ask?
Also please tell me how much time does he have