my friend has become an drugs addict and he has been died because of overdose
Recreational drugs are different from hard drugs such as heroin and opium, and are mostly harmless. Have you ever heard of anyone dying as a result of over-dose from smoking marijuana? Even I haven't tried any of these drugs till now. But that doesn't mean that I have the right to infringe in the personal liberty of others and ask them to stop consuming drugs.
I hope that will happen in the future. Already, a number of countries have decriminalized the possession of recreational drugs, including Uruguay, Portugal and the Netherlands. If future, this list is only going to expand further.