What the heck do you say to a friend dying of cancer?

I got a call last night from the mother of one of my oldest friends. To be blunt, he has terminal cancer and is not expected to be with us much longer.

We were best friends since elementary school, we were best men at each others weddings, etc… Several years back he moved across the country and neither of us has been very good at keeping in touch.

So… out of the blue I get a call from his mom saying that “his systems are shutting down” and he wanted to talk to me. I called last night but got voice mail. I will call again this morning but am at a total loss for what to say.

Suggestions?