Hi Elizabeth,
So sorry to hear about your brother.
All I can say is that I loved my brother first and foremost and because of that, even though he disagreed, but with me showing him scriptures and explaining why it's wrong, he was able to hear truth and know what God says about sin. And he'll know that anytime in the future if he wants to repent.
And he knows he can come to me any time he wants. He told me out of all our siblings which are many, I'm the only one who really is nice to him. I'm glad he said that because that means he sees Jesus in me and it also makes me think that he may feel more comfortable to come to me again in the future.
Your brother needs to hear the truth from those he loves. He may never hear it if you don't tell him.
Even if he may get angry at first, he'll see that you said it because you love him. And if he rejects you, it's not you he's really rejecting, it's Jesus and His righteousness. A person can be in church and never hear a word about the truth because many kids zone it out.
But if you speak directly to him, he will hear and listen. And sometimes things don't always register right then, but they think about what you've said later.
But first of all pray for God to give you courage to speak to your brother. He knows you love him, right?
One thing I'd suggest is that you allow him to read the passages of scripture that talks about the good news of the gospel and what it means for God's love to send His Son to die on our behalf so that we could receive forgiveness of sin and eternal life in Him.
It will be different for you, but how it happened with my brother is that we were sitting talking about life and then I told him about my new life in Christ. After discussing that it got to where he asked some questions as to why his lifestyle was wrong. That's where we used the old and new testament scriptures about homosexuality.
I would like to suggest that you be prepared. Know the scriptures ahead of time that you want to share with him. Pray and ask God to help you and most of all, let your brother know your love for him and that you want to see him have a full life of all that is good that's of God and that you don't want to see him end up in hell and that you want to share eternal life with him in heaven.
Since you said you go to church, you could make an appt to see your pastor or maybe an elder of your church. Or a youth minister if you have one. Whomever you feel comfortable with to talk to them about this serious issue.
You don't have to say it's your brother, just say that someone you know is in a bisexual relationship and ask him for help on how to approach talking to this person.
I will pray for you to have the courage. I don't know how old you are, but God even uses very young children to bring others the truth. One of my children at about 5 years old asked a person at the store if they new Jesus.
I'm almost 21 so I'm older than him but fairly close in age which I think helps.
Thanks again for the advice!