I found out recently that one of my close family members might be either or bi...it is completely...?

It is completely against my religion and her's and I don't know what to do to show her how wrong it is. If you are Christian and claim to believe in God... than how can you profess this knowing what the result of your actions will be and how wrong it is in God's eye's? I have talked about it to her and wrote emails and letter's..... it's not getting through. I know I am not perfect and I have a lot to work on, but I am trying. I am a little afraid for her and us all for that matter. She is going down and not growing closer to Him. What do I do, fellow Christians?