how long will I forgive my brother? what shall I do?

You have to keep forgiving your brother. It maybe hard as you really want to abandon him when he does the same wrong thing over and over again. The trouble is that he may want to change and probably does, but it is a sin that he is trying to overcome, a sin against his will, and he needs God's help. It would also help to pray to God to give him the courage to overcome what is wrong with him.

Yes I think you should forgive your brother if the wrong he has done is forgiveable. You should also be more of friend to him and understand him and make him realise the wrong he is doing. I am sure with a little love and understanding and respect for each other I think you can work things out. As the saying goes "blood is thicker than water."

That is your brothers own choice. It is his life. You can set the example, but it is his choice. Lots of times when people are with people that are correct, they too become correct. Forgive him. If you don't, you may find yourself making the same mistakes some day. Take it from me. I used to worry about others too, until I realized that I too am a sinner. No body is perfect. Help your brother by being patient and loving. Forgive him. Live your life, but help him where he lets you. Good luck.