My husband and I will be in Rome for 6 days after a tour. The tour starts in Germany. It goes from Munich to Oberammergau, Verona, Montecatini Terme, Florence, Pisa, and end up in Rome. Our tour ends on a Thursday morning. We are staying in Rome til the following Thursday because we want to see Pope Francis on Sunday for the Angelus and an audience on Wednesday if he is there. Other than that we really don't have any plans. My husband is a WW2 history buff and I am a foodie. Any suggestions would be greatly appreciated.
If you are staying in Rome around the 15th of August, check whether any museum/restaurant/attraction you are going to visit is open or not.
Especially true for restaurants catering to locals, most museums make extraordinary openings these days. On the 15th all public transit will run on the reduced Sunday schedules.
I've not been there, but I think Monte Cassino would be worth a day trip. One of the most notorious battles in WWII. I believe they have organized tours from Rome.
Since he is interested in WWII history, have him look at this site: thirdreichruins.com. It has photos of many places (including Munich) taken during or shortly after WWII. And then it has photos of the same places taken more recently. He might want to take a look at it before the trip so he can apprectiate the changes.
In Rome, consider a day trip to Ostia Antica. Easy to get there on public transportation, usually not crowded, and quite a step back in history.
You could contact The Catholic Traveler. He may have some day tours of Rome, with a Catholic slant, available while you are there. You can find him by googling The Catholic Traveler.
You might enjoy visiting the Campo de Fiori farmers market. I loved the food tours in Trastevere and Testaccio, offered by Eating Europe.
For WWII, haven't been there but there is a Museum of the Liberation of Rome focused on the resistance movement and Nazi occupation. It's mentioned in RS's Rome book.
With so many days, I also highly recommend the amazing art collection at Villa Borghese and seeing Michelangelo's Moses at St. Peter in Chains church. Have a great trip!