I recovered from stuttering at the age of 70! I had an abusive childhood and recovered through psychotherapy, I realized I had latent anger and resentment. I had therapy several other times previously but my childhood had never been examined. Yes, abuse can trigger stuttering. It can also worsen stuttering. The degree of abuse, the length of abuse, and the type of abuse affect sputtering. Your brother might be more sensitive than you and might view the same abuse as more serious to him than to you. Good luck, Sue