What does your husband say about all of this?

Did you write a lease agreement when he came to live with you?

Would your husband be willing to write out a contract with you that states your joint expectations of him- School/ job. Rent paid (you can always just put it in a savings account for him for when he moves out, but the prinicple of paying for where you live is important). Cleanliness, paying off the debt for the car, etc.?

Do you have terms for how long he has to get his life together and move out?

Honestly I would start with the contract-- let him fail, because he will -- then you and your husband have both agreed to terms and you can kick him out (hopefully) without much fuss from your husband!

Tell your husband you've "decided" that he has to go.  I love these men who make unilateral decisions that affect their wives greatly.

Where was SS living before? He can agree to some house rules or go back where he came from.

Your home should be your sanctuary, not a bachelor pad with Daddy's ATM card.

What was the expectation for SS when he moved it? If there were none, then you and DH need to set some. He's either in school or working full time, he takes care of his own stuff, he does not leave messes around the house, he handles his own financial responsibilities.

If your DH won't agree to that for his son, then you know that DH's own comfort and that if his son is more important than YOUR comfort. I couldn't tolerate that.