Dear DYankee,
I'm wishing you peace and strength. I hope you have some happy moments this season.
Hey, I'm sure it's a relief to know you son is somewhere safe and warm now. I would agree, however, that now is the time to move the car and other mess from your yard, AND to make sure it's clear to him and his caseworker at rehab that he needs to find a place of his own to stay.
Seriously. I can't stress this enough. There are housing options for people in recovery that are perfectly decent. There are safety nets. You have become the "default" half-way house and that has got to stop. You've done all you can for him. You're at the age now where your kids need to be taking care of you.
As to the other children hectoring you to take him in--my take on that is that they grew up seeing you abused/taken advantage of and it's hard for them to change that mindview. Also, if their late dad was a messed-up alcoholic, they might have trained themselves see him with sympathy (poor misunderstood tragic soul) and now they're seeing their big brother the same way. Which--no.
You don't have to get into a big drama with anyone. You don't owe anyone an explanation, you're not negotiating. Just, "No, he's not living here anymore." Tell that to the staff at the rehab, and to your family members. (Practice saying it into a mirror. Really!)
I guarantee they'll sputter and whine and try to drag you in. When they say "Why? But where will he live? Don't you love him?" Just calmly repeat, "He's not living here anymore. He will need to work something else out." There will be a lot of push-back at first but when people see that you won't be baited, they'll leave you alone.
Take care.