Even if it is as bad as you fear, we have men on this forum who have stayed well on hormones for many years; aggressive doesn't actually mean what you think it means. Aggressive would be better replaced by 'high risk' and your dad's cancer is high risk because his Gleason is 9 (the cancer cells are significantly distorted from normal) - but there are other factors that you don't seem to be aware of yet, such as what percentage of the biopsy cores were cancerous, and what percentage of each core. If it has taken 4 biopsies to find the cancer, then it may be only a small area of the total.
If they are commenting on the lymph nodes, that suggests that either they did an image guided biopsy or there are other reasons to be concerned about his lymphatic system - does he have lymphodema (water retention), for example?
As Peter says, your dad's prostate is huge so the PSA may be more to do with prostate size than amount of active cancer present - this would be supported by the falling rate since last year as he may have had some infection at the time.
One way or another, the hormones may do something to reduce the size of his prostate and remove the need for self-catheterisation. Out of interest, has he been on any medication for enlarged prostate or to help with urinating?