See the short biography of Napoleon II by Thomas Vance in the research section of the forum under Biographies.
Excerpts, which indicate that he was perhaps not that sheltered or ignored. His health was a problem.
"His physical training consisted of running, jumping, swimming, wrestling and riding. 'He adored horses and rode instinctively',...In March 1830 the Duke completed his formal education by taking an exam on the military code at the palace. A promotion greeted Francis in July, advancement to major with duties as a battalion commander in the 54th Lamezan-Salins regiment. Another promotion followed in November with his long wished-for appointment as a lieutenant colonel. He was assigned to the Duke of Nassauís 29th Infantry Regiment, garrisoned at Brunn. Preparing for his spring entry into full-time active service, three officers were appointed to accompany him on this first venture away from the limits of Schonbrunn...An important lesson in Francisís education about his father came about as the result of his social debut at the British Embassy in January 1831.