All I can say, after being friends with them both after it happened, and now friends with her and I'm not sure what with the male half, as we work together, is just be there. Call, email, whatever.
Me? I went over on a nearly daily basis and chatted, talked about work or my parents or my SO. They appreciated the normalcy as opposed to others who came by to commiserate and get them all worked up and crying again. It's a horrible, horrible thing, and really they just need to not be left alone. A lot of people didn't call or come by, thinking they were "giving them space," and really they were puzzled and hurt at the absence of friends.
This. Jenners and Alagirl, I am so, so sorry for your friends. As the mom to two wee ones, I just can't fathom the pain.
We couldn't all be cowboys, so some of us are clowns.
This is truly the most painful thing that can happen to a parent. What resounded with me is that you said she is an online friend. I also have an online friend, in Europe, whom I've never met. She's gone through a lot of trauma in the time we've known each other, yet we still keep chatting as we can. I know she appreciated the times I was just there for her. And really, that's the essence of all that's been said here. Just extend your condolences, and then be there for her, in whatever form.