Intervention is the process of bringing in a professional to push healing forward. Families hire interventionists when they are desperate for healing, and have exhausted their capacity to influence change with a sick loved one.
As a family member (or supportive other), you should educate yourself and become part of the team by managing the problems at home from your side.
Start calling mental health professionals, and you’ll find that getting an appointment with a psychiatrist (a medical specialist in behavioral and mental health and addiction) takes months.
People with addictions or mental health conditions run the risk of doubting their diagnosis. Whether the doubt stems from the biology of the disease process or from the psychosocial aspects of accepting the disease, the end product is the same: the mind doesn’t see its own limitations objectively.