You have some of the best ideas. I would love to get more involved in helping with programs like these. Substance abuse can be the most challenging to approach. From my experience, some people are on a self-destructive path and they forget how to take care of themselves. Some drugs are almost zombifying in that they are begin to only think about their next fix.
I would like to see more options here for medicine and research. Truly, recovery can be a long process for many and it takes time for the brain and body to heal from trauma. Some of that may be emotional trauma as well. I would love to see more options for preventive mental health services in the United States.
If you are in the US, contact the National institute for mental health. You might be able to contact your local hospital as well - that's where I ran into the social care. My ex had a person visit him for a while after we split up and I had a friend that was employed by a different hospital in the area. If anything, they might tell you where to go to get involved, depending on how much time and money you have to spare. If you are high on the time and/or money and are willing to use some of it for good use, you might be able to organize a volunteer program that works with different agencies. Even if it is just a program that makes wellness visits with or without small care packages would help some folks greatly, if they are up to that sort of thing.
What is available for drug users, I'm not sure. It seems one of the major problems in the states is that substance abuse help is difficult. Some charities help folks by donating things like hygiene items and things like that. As you said, some folks nearly forget how to take care of themselves, having fallen out of the habit for such a long time. The same can happen with some mentally ill folks.
Most importantly, though, these programs need funding. Some of these things nearly need laws to happen (like police training). Having worker protection laws that allow folks to take care of themselves would help. One of the better ways to do this is by contacting your state and local government.
I would like to see more options here for medicine and research. Truly, recovery can be a long process for many and it takes time for the brain and body to heal from trauma. Some of that may be emotional trauma as well. I would love to see more options for preventive mental health services in the United States.