Mawat55, I am so sorry for you. But yes, I am in the same position, and yes, I did the gas money and cigarettes too.
I knew my son (30) liked pot but had NO CLUE he was on anything else, much less heroin. He came to my house a few months ago to "chill out" and spend the weekend....he was cold and I thought maybe he had the flu....turns out he was homeless and going through withdrawal. He admitted he was on heroin and I have to say I didn't handle it very sensitively. I freaked out on him....as I was just so upset that he could have been so incredibly stupid, knowing full well the addiction potential. But anyway, over the next week, I was on the phone with various rehab facilities. He said he wanted to get off it but of course, he has no health insurance. He was able to get short-term Medicaid but opted to live in his car while working through the bureaucracy of getting it (which was two hours away from me). It was bitter cold and I was crying constantly, thinking of him freezing in his car. I admit I gave him a few pills to tide him over so he wouldn't suffer too badly. I bought him food, and gas so he could run the car for heat, but I wouldn't give him any more than 20 bucks. (He probably went and bought heroin with it though.)
He went into detox but wouldn't stay for rehab afterward. He came home with me, he is working (sort of) and I am just praying he's staying clean....but I really don't know for sure.
I'm only telling you this, not to make it about me, but to let you know I have been (and still am) where you are. I know we are not supposed to be enablers, but it's so hard to see or think of our children in pain. Even with their stupid cigarettes! I guess you and your husband will have to decide if you can take the step of demanding he get off the stuff and get help, or else. I know I will face that decision if I find out my son is using again. Does your stepson have health insurance? Also, do you know if there are any support groups for family of drug abusers in your area?