re: What do you say to someone who is dying?

Sorry you are having to go through this. I think the best thing to do is just let him know how much you appreciated him as a co-worker and a friend and the example he set for you to be a strong man in the face of insurmountable odds.

I'm not sure how close you are but I would suggest asking him if he has a relationship with the Lord. My biggest fear is a friend or family member passing away without my having asked them that question or them not being saved. It may be an uncomfortable conversation and the workplace may not be the location for it, but it is a conversation worth having.

Prayers, but there is no right or wrong thing to say.
Just BEING THERE speaks more than any words ever could.

Sometimes in these scenarios it works out to where saying nothing much at all is the thing to say.

But if that is not the case, or if it's a mixture of saying and embracing both physically and spiritually in silence and mourning, make sure of this one thing: Do and say whatever it is that you know in your gut you should say and do. Do whatever it is that you know you will regret if you don't do it.

Don't let the sun go down on the day with regret in your heart for what you knew you should've done and said, but what you did not do because it was easier at the time.

That, in my opinion, is the best litmus test in determining the answer to your question.

Also, even though it's one of the hardest things to say, it never hurts to tell someone that you love them if it's true and if you do and if they and you need it. Saying, "I love you man" is arguably the most powerful, most freeing, most comforting things that a man can tell his brother when the time is right for it, and it sounds like the time might be right for it.

That's what I would do.
Talk to him like everything was normal or like it used to be

Talk to him as you normally would like any other day

you say ... do you have a relationship with Jesus Christ ?
and if you can't do that, introduce him to someone that can. anything else is a waste of what little time he has left

It's mostly painless. The brain doesn't feel pain like the rest of your body. It's the cognitive and motor skills that quickly diminish. I lost a daughter to this disease.

In any situation where I am around someone who has gone through something tragic, I always act like I normally would act. I am not good at showing sympathy so I feel like I can offer them comfort by making them feel like its just a normal interaction and take them out of the uncomfortable interactions they are likely experiencing with other people. Then as they are leaving, just giving them a reassurance that if they need anything, let you know.