He is putting himself in his own hell. You just are maxed out on your patience and compassion. And rightly so.
He is sleeping in his car because he can't afford a hotel because he has no money because he can't keep a job because he drinks and any money he does have goes to drinking, yadda yadda yadda.
Lather, rinse, repeat!
Sadly, he is so in it right now that nothing you do or say will matter. There are shelters he can go do, free treatments are out there.
In the meantime, really put up your boundaries because it is clearly taking a toll.
No one is forcing him to be in the place he is. He is chosing alcohol over stability at this point.
Stay strong
