Does he have to stay with you and for long? You can't meet at a neutral place? I would keep him as far away from my space if you know his effect on you is/will be negative.

I think there is only so much "support" your T can do. When my brother was in the middle of his alcoholic meltdown and was calling me instead of our parents (I'm 9 years younger than he is, he use to care for me when I was little so the roles were reversed) because he thought they were "mad" at him and they were calling me worried, trying to learn what was going on and I wasn't in any sort of place to be able to mediate or be there at all. I called my T and she pointed out I knew what to do and if I "can't" do something then I can't do it! T's can't make it all better, less terrifying or miserable. They can just "be" (in the literal sense) there. When you go see your T when your husband's in town you take what you can from him, etc. the "sense" of him and you all's relationship. That's all there was for me, just knowing this horrible thing would eventually resolve itself one way or another and I could anchor myself on my T being there.