Dating my best friend's recent ex?

No, I'm not currently dating her nor do I like her as more than just a friend - at least not at this point. Well, my best friend just broke up with his ex and I was friends with her as well when they were together. I tried to help them stay together by consoling both of them, but it didn't work. I feel bad for her because even though he is my best friend, he can be a narcissistic asshole sometimes. I told him this straight up because I wouldn't bullshit him, that wouldn't make me a good friend. Anyways, I just feel bad for her and she is such a great girl and I know it's against the "bro code" to date your friend's ex, but what if later on, I end up liking her and we hit it off? Lets say in six months. Would that be bad on my part? Her part? He hurt her a lot and she tells me she hates him now, but would it be weird or kind of like a back stab to date her while still being friends with him? Or what if he even insisted that I date her because I'm a good guy, like, gave me the okay, would that still be weird?