Waiting around for a heroin addict to quit using dope probably isn't the WISEST choice for anyone to make. Wouldn't you agree? It's pretty self destructive actually. Like betting on that long shot horse with really bad odds. No one can tell you whether he is a lost cause or not. So you must look at the facts. He is using drugs. He is lying to you.
Is that acceptable? yes? no?
What are your boundaries when it comes to using heroin? Because right now your behavior is telling him it's ok with you that he uses heroin and his behavior is telling you that he is going to keep using.
Base your decisions for your LIFE on reality, not how you hope things or be or whether there is a CHANCE he MIGHT choose to stop lying and get better.
You don't get a second chance at life. This is not a dress rehearsal.