Hello JT: I see this is your first post here on PC. So... welcome to PsychCentral!

I'm sorry I probably cannot be of much help with regard to your concerns. From my perspective, I think about all you can do is to let your friend know you're available should she ever wish to talk about what's going on with her. However, your friend is an adult. And she has the right to make her own decisions... including bad ones. If she is cold, mean, & hurtful & lashes out at everyone, then to me what she's telling you all is to leave her alone.
My personal reaction to this sort of situation would be to take the person at their word, so to speak, & simply leave them alone unless or until they would happen to seek me out. That would be, however, my personal reaction; and I'm a pretty reclusive person by nature. Perhaps other members, here on PC may have more helpful insights to share.
Here's a link to an article from PsychCentral's archives on the topic of consoling a grieving friend. Perhaps it can be of some help:
https://psychcentral.com/blog/archiv...ieving-friend/
Also here is a link to PsychCentral's Grief and Loss On-line Resources listing:
https://psychcentral.com/resources/Grief_and_Loss/
My best wishes to you...