How do I anonymously report a drug deal/dealer who's also a family member?

The person in question is my step father. I don't know about my mother but I am sick and tired of all the drug use that's going on. Its mainly pot and a little pill popping. My step dad has also gone to several local hospitals and "faked" injuries in hopes to get narcotics to sell. Like I said above, I'm sick of this. I do not use or abuse drugs at all. I don't even smoke cigarettes. If anyone can help me that would be amazing. Also, the only income we have is my step dad's social security. My mom and I try to get jobs but transportation is limited, we do not have friends or family we can live with as our family is in Illinois. They constantly argue about various things and I don't know what to do. I'm 22 and I'm looking for work. That's as best as I can do until I get enough money saved to leave.