Drug-dealing adult son

My son is dealing drugs. He is 24 and he is a drug addict and I know now that he is supporting himself by dealing drugs. I have been wondering where he gets his money and I did not want to think the worst of him but his sisters finally told me the truth about what I already knew was going on. He is addicted to meth and to crack and he deals to feed his habit. I have tried on so many occasions to get him to stop using the drugs that he has been using since he dropped out of high school in his Junior year. He has ADHD and he could never really fit into the school system, and I think the ADHD has made it hard for him to have much success anywhere else in his life, which is part of why he uses drugs. I am scared that he is going to die. He is just a sweet kid below all the drugs and if he doesn’t OD someone is going to pull a gun or a knife on him and kill him. I am at the end of my wits and I am seriously considering calling the police on him. I have no influence to help him but on the other hand I am worried about what a felony record might do to him. He has never been to jail before but once he is a felon he is a felon for life. Is there any way I can get the police involved without having them charge him with a serious crime. I think if he could get scared enough about what might happen to him he might be more able to think about getting some help for his addictions.