Maybe it's just me, but after my grandfather died, "I'm sorry," really started to get on my nerves. It's like, why are you apologizing? Or do you just mean you feel sorry for me? And I can't stand people feeling sorry for me. "Are you OK?" is another one like that.

IMO, the best thing you can do is just be there to listen, and offer a shoulder to cry on - not just now, but in the months and years to come. She'll have a lot of support right now...but her true friends will be there for her six months or a year from now, in the middle of the night, when she can't stop crying...they'll be the ones calling to check up on how she's doing on Christmases and Valentine's Days and birthdays in the years to come...you know what I mean?

What a horrible experience for your friend, her son, and her family. I can't even begin to imagine it.