Sorry you are here, and that this is such short notice to prepare you for the meeting. My usual first comment is that your life expectancy is probably 87. I don't know anything about you, you may be running ultra marathons and likely to live to 100, or you may smoke 40 cigs a day and drink 8 pints of beer. I myself ride a motorcycle so that knocks a few years of my life expectancy.
That you have cancer is no surprise, very few men who get to 79 have not got cancer, and you have probably had it for a decade or so.
So assuming you are an average man with an average life expectancy you need to think what the next 8 years will bring. Well prostate cancer is usually slow growing, if you were 3+3 I doubt it would progress far enough in 8 years to be your cause of death. With 4+3 it probably will progress and shorten your life by two or three years.
We have had men on here treated in their mid to late 70s and we may have had people treated in there early 80s I can't remember if I have seen such posts in the four years I have been on this site.
I am going to assume you would not be fit enough to survive the operation (it is major), and if you were the prospect of a remaining life of possible incontinence would be too unappealing for you.
The next options are brachytherapy, or radiotherapy possibly both accompanied by hormone therapy. Hormone therapy improves the chance of successful RT, but you would probably be on it for two years and it would likely be quite unpleasant.
If you had brachytherapy or radiotherapy without hormone therapy it may not cure the cancer but it may slow it's progress by a few years. The problem with these treatments is they will cost the NHS about £20k. As your cancer is probably only going to cut your life short by a year or two the NHS may not think it is worth it (you may have a different opinion).
The latest version of radiotherapy is five shots over about two weeks, if it is available in your area it is probably your best chance of getting treatment. If they refuse RT see if you can get a second opinion. If you have a lot of cash ask about going private? (you can't take it with you).
If surgery/RT is ruled out. Another option is watch and wait until the cancer is showing signs of causing serious problems and then start you on hormone therapy for the rest of your life. It isn't pleasant but some people tolerate it well and if you managed to live till 83 before you started it, it would probably be effective for four or five years, so you would get to 87 without dieing of cancer.
As I know so little about you or your diagnosis I have had to make a lot of assumptions. This is the best information I can give you at short notice.