Okay, so even if the theory is correct and your husband is only abusive when under the influence...he's going to be in your home with you for a week with rehab coming up in one week. Last time he was looking at that scenario he used, drank, and he was abusive to you and to his parents.
I hope you have your boundaries clear in your mind and that you have an escape plan if you need it? Sometimes we can over-intellectualize ourselves into big trouble.