Over the years I have met many people who do not believe they can help a person suffering from alcohol or drug addiction because they have never experienced it themselves. This is far from true. It is true that having information regarding addiction can be helpful but, it is not required to be an encouragement to someone suffering from the despair that comes with their drinking and or using.
What people need most is someone to care. They need someone to listen without judging and instead of trying to fix them just love them. The addicted already know that their behavior is wrong and destructive even if they don’t admit it. What is most helpful is to establish an open relationship with them that when they are feeling remorse or looking for someone to share their fears and despair you would be someone they would turn to.
In the meantime, be the best friend you can be.