Thank you for sharing. It is truely amicable that you are reaching out to others in concern for someone that you care about.

There has been research done which supports the power of positive thinking. If your friend were to focus on future goals and were to live on as someone who wasn't having to struggle through such a horrible thing, he may extend his life. In addition he can work on mindful meditation. When done properly, this also has a profound effect on sort of rewiring the brain to produce more positive thinking and positive feelings.

If at all possible maybe do as much research as you can and share this with your friend. I believe that just by you being there for him as someone to talk to, even though you cannot fully understand what he is feeling, will be more helpful than you may know.

I hope that this gives you something that may help, even in the slightest. I also hope that others who have different perspectives and experiences can give their advice to you as well.