Well, I got the bad news I was expecting from

[dickthegrouch]

13. Always treat him as if he's not dying

Semantically he's not dying until the last few seconds.
But treat him as normally as possible on any given day.
He's just sick, not dying. You both know the reality, but allowing him to experience life as he chooses, is the best gift possible.
If you can, take him out. Go to games, concerts, parks, whatever.
Suggest things in your price range (for both of you) in case he can't afford it. Tell him it's your gift to him.
Have a plan for emergencies, but don't feel bad if the plan doesn't work. He was living the best you could help him to do.
Miserable people all around him will see him off faster. You can be miserable afterwards.
Remember the last thing to go (apparently) is hearing. If you can, tell him you love him as he passes or very soon after.
Make sure you have access to him for the entire time. Even if it means asking him to write a medical proxy for you.

Hope that helps.