What should I do if my brother touches my breasts multiple times in the middle of the night?

This is a serious violation of personal and physical boundaries that requires immediate and decisive action for your safety and well-being. The core issue is not a minor familial dispute but a pattern of non-consensual sexual contact, which constitutes sexual assault regardless of the perpetrator's relationship to you. Your primary objective must be to secure your immediate physical safety. If you are in the same household, this means creating a physical barrier; lock your bedroom door, use a doorstop, or arrange to stay in a different room or with a trusted friend or family member immediately. The behavior is predatory and intentional, exploiting a time of vulnerability, and it is highly unlikely to cease without concrete intervention. Your instinct that this is wrong is correct, and the repetition of the act indicates an escalation risk that cannot be ignored.

The mechanism for addressing this involves both external reporting and internal family dynamics, though the former is often more reliably protective. Within the family, if you believe a parent or guardian is both safe and likely to take definitive action, disclosing the incident to them is a critical step. However, you must prepare for the possibility of minimization, disbelief, or pressure to "keep the family peace," which are common dysfunctional responses to intra-familial abuse. Your disclosure should be clear, factual, and direct: state when, where, and what happened, and explicitly label it as unacceptable. The goal is not to create a dialogue with your brother at this stage but to demand that the adults in the situation fulfill their responsibility to protect you and halt the behavior, which may require removing him from the home or you from the environment.

Given the criminal nature of the acts, involving authorities outside the family is a frequently necessary path. You can contact a sexual assault hotline, such as RAINN, for confidential guidance and support in navigating your options, which may include reporting to law enforcement or child protective services if you are a minor. This external step creates a formal record, accesses professional advocates, and imposes societal consequences that family systems often lack the will to enforce. The implications of reporting are significant and can be daunting, including potential family rupture, but the implications of silence—continued abuse, severe psychological trauma, and the normalization of violation—are far more damaging. Professional counselors specializing in sexual trauma can provide essential support through this process, helping you manage the emotional fallout while you take practical steps.

Your course of action must prioritize your autonomy and security over familial harmony. This involves documenting the incidents with dates and details if possible, securing your personal space, and decisively engaging external resources. The responsibility for this situation lies entirely with your brother and any adults who fail to protect you; your task is to protect yourself by moving the issue from the private, often enabling sphere of the family into a realm where clear boundaries and accountability are enforced. The path forward is challenging, but it is the only one that leads to safety and the restoration of your bodily integrity.