I think the less you say to boss the better. If it was a constant thing where she turns to you for help with him, then maybe speak up and let her know that she needs to work this out with him and not put you in the middle. But since this sounds like a one time deal since he left, maybe just get the passport to him and let it go.
Just something to think about, but it might be less stressful for you to just let him come, while you are home, and pack up and remove his own stuff. Emotionally, it will be just as hard on him as it is on you on some level. For your sanity, the sooner his stuff can be gone the better. Look how much time and emotional energy you have already spent on this. Time that could have been spent getting a massage, shopping for shoes, eating bon-bons or whatever you like to do to pamper yourself.
As for your text/email to him. It sounds so formal. If that is what you are going for, great. But maybe soften it up a little? Speak to him like you would speak to the man who lives across the street, friendly but not overbearing.
Me: 42 H: 45 M: 18 yrs T: 20 yrs D: 17 D: 15 S: 12 I kicked him out 8/21/15 I will DB until March 21st 2017, that is it!