Well, why not call and see who will be on-call for him, and how to reach that person? That's quite normal to have that, for emergencies.

Well, then I guess you're calling him caused him to ask his assistant if she had taken care of changing your appointment..and she hadn't yet? So it's good that you did call, out of the ordinary, so you weren't thrown the curve next week.

I know it's tough when T goes out of town... if you can use that time for yourself, for something you wouldn't normally have time to do, then it will become a respite for you too.