The good news is that he is in treatment right now so you can relax and just focus on taking care of yourself and your children for the time being. He may be getting out of rehab in four weeks; however I am pretty certain there is nothing that requires you to finalize everything before he gets out. It is certainly not your responsibility to find a place for him to live, but if you think it would be helpful for you to have someplace else for him to go when he gets out then you may want to consider it. My only advice would be to discuss any and all options with an attorney before you do anything else. Also take some deep breaths and relax.