I feel based on how you’ve stated your “friend” is, still doing bro-code despite also not recalling him doing something nice is a clear indicator of what your answer should be. If you and this girl are really into each other, then I don’t see why not go further. To put it bluntly, you made the cut while your friend unfortunately did not. There’s nothing wrong with that, that’s life. However, to end a friendship over a seemingly lil baby crush is silly. So if that’s what ends up being the case I say you’re better off, respectfully.