Bottom line, he is an adult who deserves respect, respect you will not apparently give him. You are treating him like a child incapable of making adult decisions. You don't hahve to agree with his choices. They may be bad choices in your eyes. But adults have the right to make bad choices and to learn from them (if, of course, someone doesn't sweep in and save them from the consequences of those choices).
If you want to continue to try an control him, to be responsible for his choices and his life, you are of course free to do so. But do not try to convince you are being anything other than a codependent enabler who is not ready to let go your drug of choice. Accept responsibility for your choices and their consequences. And don't expect a different result from doing the same thing over and over.