Don't feel bad about yourself. We all were like this at first. Let me give you a few tid bits that will make you feel better.
1. It is really hard to not eat in the U.S., even homeless, unless you don't WANT to eat. Some druggies are never hungry due to the drugs. If someone with no permanent address wants to eat there are food cards, many food pantries (these are all over and easy...and cost free) and shelters feed the homeless. The food is really good...i volunteered at a homeless shelter. Church ladies made home cooked meals. No, they wont starve and don't need us in order to eat. This is an easy need to fill even without a dime.
2. Our rather disturbed adult kids do not seek out good help if WE become their help and we don't have any clue what to say or do for them so we tend to do for them what they can do for themselves and inadvertently teach them that they can't. They feel powerless and helpless about washing a hoodie. Or blowing their nose Without us to hold the tissue. Yet they are great at kicking off great drug deals. They are smart and capable in areas where we would never get involved. They are actually capable in most areas but we often see them as still tiny kids. I'm, they are grown ups.
3. Shelter...there are shelters. Some won't go because they have curfews and rules about drugs. Too bad, so sad. If they live in our homes they are mostly out in the streets anyhow, abusing us in ways we wouldn't allow from anyone else and demeaning us and breaking every house rule and taking, taking, taking. Our retirement money goes bye bye and they sure won't be there for us if we give it all to them.
4. The cold...invest in a warm coat (not expensive, they will sell it for drugs), a warm face hat, gloves and boots. I live in Wisconsin and normal cold weather even here kills nobody. During the day many places are open for warming up, like the library and malls. At night there are shelters. Some laundomats and Walmarts are open 24/7. More than that, our difficult adult children are incredibly street smart, learn to couch surf, and the homeless community, mostly drug users, help one another and look out for one another. They build fires, share food, give company.
This is not what we want for our adult kids, of course, but many of them don't mind it; would rather live nowhere than follow any rules. Nobody can be the boss of them.
I read a book written by a young adult who left his family home due to rules and a step dad he didn't like and lived on the street for a year, refusing his sister's offer of shelter at her place. He sounded as if he enjoyed it. He certainly didn't starve or get lonely.
Yep, they are NOT like us.
4. If they are mentally ill, most have MINOR mental illnesses, like I have, such as the highly treatable disorders of depression and anxiety. However they refuse help, often declaring that marijuana is the best and only treatment for them, which is nonsense. But we can't help steer them toward help if they won't accept it. You can lead a horse to water....but if he is a human horse he can say "f******* no!"
If the adult child is very mean, hurts us and/or steals from us, he probably has a personality disorder and can be dangerous. There is currently no proven help for people who have no conscience or empathy. The best we can do is protect ourselves from this sort of person, even our own child. Other loved ones need to steer clear too.
The only person who can help somebody else is that person, not us. They are adults.
My daughter who quit drugs acted mentally ill when she used, but she isn't, and is very sweet. But she only quit when she wanted to. Your son will not get better one day before he wants to, if the day arrives, and if you force him to stand on his own, he WILL survive. Or not. Living in our home, when he is even there, will not keep him alive, if he is bound and determined to destroy himself. Most overwhelmingly likely he will survive, no mattert how little you help him.
They respect us far more, even, if they swear at us, if we stick up for ourselves. They look down on us if we let them kick us in the heads. No kid respects a parent who will do anything he/she wants.
With all that said, take what you like and leave the rest. Do what you must and remember nothing changes if WE don't change.
Love and hugs