Unless you know that your old friend is poverty stricken, and never knows where their next meal is coming from, please, please, please do not send her money, as I believe that that would be a totally crass thing to do, and just wrong in so many ways. If you believe that, without actually being in poverty, your old uni friend will struggle to pay for all the expenses that will very sadly be coming up, then could your other friend, ask your uni friend's grandmother, whether her daughter would appreciate a 'go fund me' being set up in their name. I know that some people would hate it, including me.
However, if anyone reading this thinks that is also a crass idea, then please don't even suggest it. If they would like a 'go fund me' setting up OP, I think it should probably be done by someone much closer to the family. The grandmother must also be feeling devastated, so I hope your other friend is both tactful, and a good communicator.
I know that when we hear about awful cases like this, the natural reaction is to want to do something to help, and it can be horrible to feel so powerless, but I think that we all, and I am including myself here, need to think about what we want to do, and whether it is solely because we want to help the person suffering, or whether it is partly to make us feel better as well? In which case we have to remember that none of it is about us.
I agree with PPs that a few lines expressing how sorry you are, and that maybe, as you live so far away, and therefore can't, unfortunately, offer any pratical help, that if she ever wants anyone to talk to, or even rant at, night or day (if you actually mean that), then to please give you a ring, as you hope that you are a good listener, and that you wouldn't offer any unasked for advice, you just want to offer support in whatever way you can, and she needs.
Personally, I would add that she doesn't need to reply to you now, or even at all, and to just ring if she ever needs someone else to listen to her. I would probably add that I hoped she was able to take as much care of herself as possible, so that she can be strong enough to be there for her dear child - and any other children if she has any. One last thing, please send your thoughts by snail mail, not an email, or anything else digital. Thank you for wanting to be there for your friend, we need more of you on this struggling world. xx