You can't fix people. No matter how much you want to. No matter how hard you try. People don't want to be fixed.
You can't keep trying. You can't keep getting in between them. Listen and don't speak.
You can't fix them. They have to want to fix themselves. If they don't, then let them go. If you can't….then try. Try to accept that you can't change people. Try not to hate them for not changing.