What is a true friend?

I have a friend. Allegedly lacking self-control. Seems like she can't resist taking a drink. Imbibing in alcoholic beverages. To excess. But I argue that she can take control. Others have done it. So can she. Therefore, I am tempted to give my friend an ultimatum. Stop drinking. Or lose my friendship. I leave no room for forgiveness. Makes me wonder. If I'm a true friend. If I don't forgive my friend's transgressions.  --Jim Broede