Welcome back Karen.
I believe you are doing the right thing.
I would go further, but that is me. I feel that when our children are behaving self-destructively and the behavior puts them and others at risk, we give them a mixed message when we continue supporting them at college, or allowing them to live in our home.
To me, the substance disorder trumps any other thing that they may or may not be doing and needs to be addressed first to justify continued support. I seem to be in the minority in this, but because the drinking or drug use is so potentially deadly, I feel I need to say it.
While I am old now I supported myself 100 percent through university and graduate school. I paid rent, tuition, food--everything. Younger than him I found apartments and jobs. I bought cars. College is way more expensive but kids do it that do not have parents in a position to help them. Your son will find a place to stay.
I do not see how you could not have done what you did--told him no more. He is flaunting every rule you have imposed, and flaunting common decency. You have younger children who are vulnerable to this. What choice did you have?
I see no other option that you could have taken. Your son forced you to it. You had to respond.
I hope you keep posting. Take care. Take care of yourself. The elephant is in the living room. You said, leave.
He is a man now. He is defining himself as such by his insistence on doing what he wants when he wants it. You are respecting his decision. Try not to take this on yourself.
COPA