I see folks are tackling your marriage, which I don't think is what you had in mind, did you? I can see their point, though.
Our 26-year-old son is living with us this semester--and he lived with us for awhile when he was discharged (medically) from the service. We are going to have him pay some rent, plus do some work for us. He is working part time while finishing his Master's.
It does occur to me that your SD has your hubby as a role model. Has he always smoked pot or has that been more recently? Do you have somewhere else you can live for awhile if your SD moves in with you? Sounds like hubby and SD need a wake-up call. It's a shame they are more than happy to take advantage of you.

I hope the SD gets to work somehow. The Army would certainly help grow her up! I gather your hubby hasn't asked her what she wants to do.
I honestly think you could benefit from some counseling. It has certainly helped any door-mat issues I used to have.