2. Actively communicate with your younger brother. The lack of communication between family members has aggravated many contradictions. So you usually communicate more than your younger brother, so you can start with what he is interested in and gradually gain his trust.
After gaining your brother's trust, you can make full use of your own experience to convince your brother, tell him your own experience and let him realize the harmfulness of doing something. But in the process of persuasion, you can't always say the bad part. You can tell your brother what will happen if you obey.