FWIW, I think it is a loving and appropriate thing to comfort a friend UNLESS she has asked for no contact or unless you think it would hurt her or you.
I take it you would not be reaching out to her to promote your own agenda -- to make her think twice, to show her how great you are, to make her need you, to show her how dumb she was not to work things out with you, to get her family on your side... Early in the process, it's pretty normal for LBS's to latch onto these moments to advance their own agendas even as they feel like the noble holier-than-though suffering martyred LBS. THOSE are the times in which it is inappropriate to reach out.
But, I hear not a smidge of that coming from you. There is someone you care about facing unknown loss. It seems you have a genuine wish to offer simple comfort stemming from compassion. I think it would be fine to take her a comforting something-to-eat or drink, give her a hug, be there, and listen.
