HELP- Concerned for a friend

Recently a close friend of mine stopped responding and is posting online about them being back with their toxic ex. This person they're with has literally threatened to >!off himself!< in front of her if she tried to leave. He's threatened similar things multiple times. He's extremely manipulative and at this point I'm fully concerned she could be being held against her will!

She told me all about him being abusive and bad to her. She said she was blinded before but she's past all of it. I just can't believe she could ever willingly go back to something like that given how she described it.

I'm trying to reach out to her inner circle, family, etc but haven't heard back from them yet. My worry is growing by the second. I want to know if there's anything else I can do other than sit on my thumbs here