I appreciate you asking this difficult question. It is hard to love someone who is addicted. Let’s see if we can sort some things through.
In your desire to help your friend you see his potential. You can’t see what his abilities and capabilities are. But when someone is immersed in compulsive drug use, they don’t fully realize what is happening or what to do about it. You see it clearly and this is what causes the anguish.
The struggle to find a balance between wanting to help and knowing you may not be able to has been experienced by many people before you.
Because you live in another country I am not familiar with the availability of Al-Anon or Nar-Anon meetings. These are 12-step meetings for people involved as family or friends of people abusing or addicted to alcohol or drugs.
If there are no meetings I would strongly recommend reading the book Codependent No More by Melody Beattie. This book specifically talks about how to untangle from this by detaching with love, and focusing on yourself.
The best thing you can do for your friend is to know you are limited in helping him, but that you still care. This requires you to be strong enough to manage your life and continue to grow, while not letting his struggle with drugs become a drain in your life.