First of all, it is impossible to "change" someone. He must WANT the change before he will EVER stop doing drugs. He needs help...because the fact is ...is that the drugs will come before you .....unless he wants to do something about it. Let him know that you love him and you are there for him....but you can't FORCE him to stop using. Let him know that you want more out of life! He has got to want to change for HIMSELF...not just because you want him to...although it should be great motivation for him. But, too, you are only human, and you can only take so much of being 2nd to drugs...eventually you will get tired of it....especially if he doesn't realize he needs the help!