It is possible to help people who are homeless in the USA who are neither mentally ill nor drug abusers. The mentally ill are incapable of accepting or using the help available to them. The drug addicts prefer the drugs and being homeless to being off drugs. There is more than a little help available for people who want to quit drugs and if you want to see what kind of support is available for the homeless in the USA visit San Francisco, the only first world city I am aware of where one regularly has to dodge human faeces in the street.
I'm not saying they don't deserve help. I'm saying that your money can do more good elsewhere, which is not something I'm willing to argue as being blatantly obvious. If one subscribes to the idea that there is a continuum of "deserving" to "undeserving" poor most of the drug addicts fall under undeserving and the USA is no longer willing to imprison people indefinitely for being mentally ill so they're probably beyond help. Very possibly also better off because mental hospitals are the closest I have ever seen to Hell, but beyond help.
I'm not saying they don't deserve help. I'm saying that your money can do more good elsewhere, which is not something I'm willing to argue as being blatantly obvious. If one subscribes to the idea that there is a continuum of "deserving" to "undeserving" poor most of the drug addicts fall under undeserving and the USA is no longer willing to imprison people indefinitely for being mentally ill so they're probably beyond help. Very possibly also better off because mental hospitals are the closest I have ever seen to Hell, but beyond help.