In love with my best friends brother?

I need help, advice, or just guidance… so my best friend and I have been best friends for as long as I can remember .We are childhood friends now that her and I are both in our mid 20s, I honestly consider her as my sister. Well growing up together she had brothers and one of her brothers frankly, was a dick to me and has always been. Let’s just call him Jack, but over the years jack and I have grew kind of close… close enough that I am starting to actually have feelings for him and he has feelings towards me as well. So now I honestly try to avoid jack because I don’t want my BFF to have any ill feelings towards the whole thing. The other day my BFF asked me if jack could move in with me because I’m looking for a roommate. Since the whole virus and everything I’ve been struggling and I told her ill think about it. Well that day goes on and we all decide to go to the pool and day drink a little bit and I guess jack was checking me out “neck breaking.” As my best friend said and because I smiles at him and kinda flirted, my BFF asked me if anything is going on between him and I because “it will gross her out and piss her off.” If anything did happen well I told her no nothing has happen but I was honest about the feelings that I have for jack… well she went on and on about how bad it would be for us to be together and I could be better and how much she actually hates her brother ( which is not new, they fight all the time .) I don’t want to pursue a relationship with her brother if it’s going to end a friendship with my best friend I love her to death, but I also feel that jack and I have a real potential to be something amazing… I’m just asking what would you do? I feel like a bad friend because I know it’s wrong I’m just stuck and looking for some advice. Thanks for reading

You like who you like & you can’t help that. It’s good you were honest about how you felt towards him, & maybe she’s just a little jealous about the fact that you’d be spending time with someone else. Also, totally normal. If it were me I would see where it goes with him. I wouldn’t hide it from her, if she asks something tell her… but it would hurt her a lot more knowing it’s been happening behind her back. I’m not sure why she’d be so upset about it, I wouldn’t care that much if my best friend and brother were a thing