Since my diagnosis with a life-threatening disease, I have had many conversations with many friends that usually, at some point, hit the sentiment that my friend is afraid to say the wrong thing. There are many more unrealized interactions with friends who are so afraid, they can't speak at all. That's a shame, if ever there was someone to practice on, I assure you it's me. I believe that even the wrong thing said from the heart, without malice or bad intent, is the right thing. For me, worse than saying the wrong thing is avoiding me.
But that's me, and that's not true of everyone.
Susan Silk and Barry Goldman, in an op-ed piece for the LA Times, suggest the "ring theory" in choosing one words in all crises - medical, job loss, divorce, death.... Their theory says to comfort in, dump out.
In short, imagine the person of concern in the middle of concentric rings. It's their job loss, diagnosis, crisis...they can say anything to anyone as they come to grips with their new normal. In the next ring is a spouse and the kids. They may have concerns and feel like complaining about the situation, but they can't do it to the person in the middle, only outwards to the next circle. That may include the employer, and very close friends. Outwards from there is associates, parishioners, friends and extended family. And so on. (This incidentally is the exact order in which we announced my cancer; we actually thought of it in terms of concentric rings and started working from the middle out.)
So while you may wish to tell the afflicted that life isn't fair, it shouldn't happen to such a nice person, etc. that is exactly the wrong thing to say to the wrong person. Believe me, I know first hand. That kind of talk comes with an expectation that the person will offer you comfort - which frankly, I haven't the energy to do for outer circle friends and associates. Offer me, offer my wife and kids words of comfort instead, and save your complaining to the person in the circle further out - your husband who's never met me, for example.
Here's a link to the original article. If it won't help you in dealing with me, don't worry, you'll have lots of practice as life goes on and reality hits someone you can't avoid. http://goo.gl/ZOKxr