Will this stay with me for the rest of my life if i dont get help? :/?

This is gone on for two years too long. You must tell your mother everything that happened and everthing that is happening in every detail. Your brother is very sick. He needs a whole lot of help. And he won't get help as long as he lives in the same house along with the rest of his family. Your mother and father may be reluctant to do the right thing because your brother is their son and they will be afraid of the scandal. So if they hesitate at all to call the police, talk to a teacher or counselor whom you trust at school. The school has legal responsibilities to you, as do your parents, but the school won't be afraid of the scandal. They will call Child Protective Services in your county Department of Social Services, and they will know what to do to take care of you. You urgently need psychological counseling. Taking action will require all the courage you've got. It will be extremely difficult. But, believe me, this is something that you absolutely must do for your own sake, for the sake of your brother, and for the sake of your parents. If you fail to take action now, you will be setting yourself up for a lifetime of serious mental disturbances. I wish you the best.