It sounds like your brother has grown into a wonderful young man and that is awesome. I wouldn't bring it up to him but I do think you should confide in your therapist about the situation and how it has made you feel all of these years. Your therapist can help you heal so that you can put it all behind you. I doubt very seriously if he/she will try to contact your parents, brother or anyone regarding this as your sessions are all about you and your feelings. Therapists are supposed to respect their patient's concerns and confidentiality. I wish you peace and happiness.