Oh gosh. First off you seem like such a lovely guy. That was such a kind and thoughtful message that you sent to you friend and she's lucky to have you looking out for her.
You won't like this, but I don't think that there's an awful lot that you can do right now. It isn't super-common, but abusive people can recover and become non-abusive people. (I'm not just making that up, I have a friend who works in the field who acknowledges that it can happen). So that's something to hope for at least! There is of course a bigger chance that you're right and that she's back in an unhealthy relationship and if that is the case, he may well have control over her phone or other messaging devices so you need to be careful. Whether through her choice or not, it sounds like she's not using any communication channels of her own at the moment, which means you can't even continue a casual conversation, which at least creates the safe space in which she could start to share if she wanted to. How would you feel about contacting the guy as requested in that status? I'm guessing whatever country you're in is currently in lockdown, so contacting via the boyfriend to arrange to meet up isn't going to work, but you could ask if she'd like to talk on the phone to catch up?
In the long term hopefully she'll be back in direct contact with you, in which case I'd advise being careful as mentioned above. Feel free to ask light questions about her relationship, but if she shuts down in response try not to take it personally- she might not be ready, or it might not be safe for her to talk about. It will be obvious to you that she should leave, but for her it's a lot more complicated and try not to get exasperated by her - you can't make her reach the decision to leave, but you can be a consistent and caring friend to help her on the way to reaching that decision herself.