We can't be in a relationship (like kind of ever)

So me M 20 and and my crush F 19 are kind of in a problem where we can't be in a relationship (like almost never). The problem is her ex/(self proclaimed current) bf.

He 's a literally a criminal M 20 . They both got in a relationship when they were in high school and she was abused mentally and was used by him for his pleasures.

She being so naive and scared of him and his brothers/friends who are also yes criminals can't get out of the relationship. She has currently told him that she needs a break and that she is more happy with her current friend group (which includes me and our mutual friends).

He is extremely suicidal ( to make her feel guilty ) and has threatened me and my best friend to stay away from her or he will kill us.( Yea ikr sounds like a movie).

If she tries to break him off then his brothers will come at us too..

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She told me that we are perfect for each other and she feels the same way as me . I really want to help her but i don't know what to do . We always joke around by saying all the cheesy pickup lines with each other and other cute things but we know we can't make it mean a single word because then we both will get hurt soo bad. It's like I found someone who can finish my sentences and i can finish hers. I don't wanna lose her but if that's the only way she becomes safe then I would do that too. Even the universe is giving us signs to get together but we can't .

I have come here as a helpless and hopeless person asking for advice from you guys.