Drug de addiction and therapy. Guide.

My close family member age 24 has got into drug usage in his office space.We confronted and inspite of talking wid lov and even scolding later on he is frequently under the influence of the drugs. We feel its been three months he has been into it. Comes home in no senses..has no idea about the money in wallet and has lost a expensive phone. Request you to pls guide for course of action as we feel he wud not go to any counsellor or doctor (hospital or clinic). After being under influnce for next 24 hrs he shouts on being confronted that we r calling his friends or asking him. There is no reason except influence of company that he has got into this habit. With just retired parents at 62 age he has no concern of father being a heart patient. Pls guide.