I am really very sorry to know that your big brother shows bossing with you and his attitude is not acceptable. The people very close to you are definitely your parents. Let them know all about him and seek help. Just in order to solve the problem, you need not respond to any misbehaviour or misconduct of your brother. Try to forgive his old behaviour and show that you don't hate him. Send him wish card and small gift in order to make the situation soothing. Talk with him in a respectable manner whether he adopts harsh attitude. Insha Allah you will see a positive change in near future.