Twink, a family pic is just perfect for your family and your dad. And get a print of it for him so it can be near his bedside and he can see all those he loves on a daily basis.
His attitude's dang good. That'll help. And knowing that HE knows he's had a good, long, and interesting life will help you in the long run to keep some perspective on things.
At least this way he has some control over the terms of how he goes out. It still isn't going to be easy. I have to say that some of the most beautiful memorial services I've been to have been planned by the person being memorialized.
The photo site is beautiful. Make and keep the memories now. Make a living legacy with him.