Change can be tough on these babies. It would be so much better if we could just talk it out with them so that they'll understand.
I actually did this with Annie and I don't think she understood the words, but I do think she understood my tone and often it did seem to help her deal with situations. So as crazy as it sounds tell him this is ya'lls new home and how much you like it here and all the wonderful things ya'll are going to do together, where you are going, when you should be home, have a good day, mommy loves you, etc. One thing I learned fast was to never say something along the lines of watch the house. For some reason when I did this she'd start whining before I even got out the door and there would be things strewn about all over when I got home. I think it stressed her out to think she had to protect the house.
Could you afford a dog walking service for a day or two? You should be able to find several reputable ones in the DC area. You could also try leaving a radio on for a little background noise. Hide treats all around the house for him to find throughout the day. And walks, walks are very important. Going out and coming back - together - helps to establish your new place as 'home'. Besides the fact that they need the exercise for their health and mental happiness.
And last but not least, talk to your neighbors or at the very least leave them a note, explaining that you are aware that Izzy is making some noise when you leave and that you are diligently working on correcting the issue, apologize for any inconvenience that it's causing and that you greatly appreciate their tolerance during this transition time. Who knows, you may just meet your next best friend this way.