Thank you for writing. Clearly you and your mother need some help with a situation that is becoming more and more desperate. Unfortunately, there is little you can do to help your brother if he doesn’t want to help himself. You can’t make him get treatment. You can’t make him stop drinking and smoking.
What you can do, though, is take better care of yourselves. I’m very worried about your statement that you are afraid for your and your mother’s lives. Although you didn’t state it, I’m guessing that your brother lives with you. If she feels she can, your mother needs to set conditions for continuing to live under her roof. That means contributing to the household financially, doing chores and seeking some treatment for his depression.
Sadly, your mom is between a rock and a hard place. If she doesn’t ask him to leave, she’s enabling his habits. If she does, she fears he will end his life. The third alternative is to try an intervention. For that to be effective, you and your mom need some guidance.
I suggest you do a couple of things: First, see if there is a chapter of Al-Anon nearby. Al-Anon is a self-help organization for family members of alcoholics. Meetings can provide you both support from people who know what it’s like to both love and fear a family member who is using. Second, ask your doctor for the names of local therapists who specialize in substance abuse and make an appointment. An experienced therapist can help you and your mother manage the situation and give you practical advice about how to run an intervention if that’s what you decide to do. Once he or she understands your family situation, the therapist may also know of treatment options your brother might accept.
I wish you well.