ErinA

That loss sounds absolutely horrible. I am sorry for your sister. I had a loss at 20 weeks after a lot of fertility struggle— not nearly as late as your sister but late enough that we thought we were out of the woods. A few thoughts, some of which echo what others have said and some of which may conflict:

1) In any grief or difficult situation, specific offers (ie “would you like me to bring you dinner?” As opposed to “I’m happy to help”) are always great. Even if the person says no, that means you know more about their needs and preferences.
2) Having close friends tell others was something I really appreciated. I did not want every interaction to have to be about the loss.
3) If your sister had already set up a nursery or received lots of gifts, offer to pack away the baby stuff for her. Baby clothes are not adorable when you just had a loss.
4) For some people a late loss means they lost a BABY who had a name and a relationship with them, and they want to have a funeral. For me it felt like I lost a PREGNANCY that I had worked at for over a year and I didn’t love baby language. Either way, pay attention to how your sister talks about the loss and follow her lead.
5) As others have said, keep checking in! With any loss, most of the support comes in the first week or so and then other people go on with their lives while you’re still grieving. I needed people to talk to and ask me about other things so that every conversation wasn’t processing my miscarriage, AND I needed people to occasionally ask how I was doing weeks and months out.

Last, your sister may not want to be around babies or pregnant people for a while and you may be able to help her steer around those situations. And I don’t know if she has a partner, but sometimes the non pregnant partner gets forgotten and they’re grieving too while also likely supporting their partner. So make sure you also check in with the partner.