Her book is really quite interesting.
The events that happened in the musical, in reality, took place in a different time frame – they had been married for over 10 years when the family left Austria… the kids were much older ( the eldest son was a physician at the time ) and Maria and the Captain had younger kids of their own.
They WERE hard-core Austrian patriots ( the captain had a 30ft Austrian flag hanging in the grand entrance of their home ) and cash-poor at the time they fled, as the captain had patriotically moved all his investments into an Austrian bank during the years leading up to the war …and he lost it all when that bank failed.
They had dual Italian citizenship and left for Italy by train on their Italian passports, getting out shortly before the borders were closed. Captain VT had a small amount of money waiting for him in Italy - just enough to get the family to America - aside for that they walked away from everything they owned when they fled - (they did get it back after the war.)
Their life had been uneasy in Austria under the Nazi’s…they refused to display the Nazi flag, the younger kids were repeating anti-German sentiments they heard at home in the wrong places and the Nazis had made them several “offers they couldn’t refuse” - a military commission for the Captain, a singing tour for the family and a staff physician job for the eldest son. So they left.
Another fun fact --both of their sons enlisted and served in the US military when the US entered the war.