The hard part is over.
I'm matching you with one of our specialists who will be calling you in the next few minutes.
Since it sounds like you have time, you should start slowly. If he goes somewhere like a club every Monday, try to get him to let you take him and pick him up for that one thing (or go with another friend, or take senior transportation). Then he can drive the rest of the week. Eventually, he'll see he can still go places. Maybe then you can move to two events a week, and so forth. Obviously, this is if he's still capable of driving at all.
The main thing to that you need to research how he will get where he wants to go if he can't drive and slowly let him know that he will be able to do so. It's hard, and he won't like it.
I tell nearly everyone that they will need the third party help of a doctor or good friend or spiritual leader - someone outside of the family that the person respects. It's easier for an adult to hear this message from someone other than their "kids." That's a general statement, of course, but is nearly always true.
Some people, because they have done everything else and still can't get an elder to quit driving even after they've been tested and shown they can't drive, have gone so far as to disable cars. It can get ugly.
If you have time, start discussing this with him. Go to The Hartford Web site and AARP. They both have good material on helping elders be safer drivers for as long as they can, and help with driving cessation. Good luck with this. Your kind heart shows through.