I was just thinking, since younger sons typically went into the military and the clergy to make a living, does this mean General Tilney was a younger son who (eventually) inherited Northanger Abbey?

In a way, he set a good example by making both his sons have a useful occupation (the older one a captain, Henry a clergyman), but how would Captain Tilney learn how to manage the estate of Northanger Abbey while fulfilling his officer duties?