Concerned for a friend

She's been confiding in me recently and no one really knows what her relationship is like on the inside. For some reason she's told only me and after seeing what it's like I would simply describe it toxic. I discovered they've already broken up twice before, he as self harmed and blamed her for it, called her narcissistic, b!tch, selfish etc. and basically he puts his issues on her from what I gather.

I'm concerned cause she has her own issues and is sacrificing other things to try and be there for him because somehow she still loves him a lot and tries her best. But when she starts messaging me I don't know how I'm not enough for him, and how he said he doesn't know if she loves him its like idk what to suggest I don't like telling people they should break up because it should be their decision not mine. But I'm still concerned the toll it's having on her. Do I just keep consoling her or do I be real and say it for what it is.