Does reporting a drug addict – who has been previously advised but did not respond, and has children – count as harming him?

The harms of drugs are known to all. Islamic Sharia came to achieve benefits and ward off harms.

Anyone who consumes or deals in drugs must first be advised. If the advice is not effective, then reporting them to the competent authorities becomes necessary, due to the Prophet, peace and blessings be upon him, saying: "Whoever among you sees an evil, let him change it with his hand; if he cannot, then with his tongue; if he cannot, then with his heart—and that is the weakest of faith." This reporting is religiously required.