Is there an adult you can talk to, who you can trust, and has your brother's trust as well? Someone who can offer you support and will help you find out what is affecting his moods so drastically? USING AND SELLING DRUGS IS A SERIOUS MATTER! It is an illegal activity. You must get an adult to help you out. This is beyond what you can do by yourself. If a drug problem does exist, there are counselling services in this city that can assist you in taking the next step in helping your brother.