Anything about the British royal family is an interesting topic, including the possibility that Queen Elizabeth II could outlive her son and future king, Prince Charles; although it may not happen, still, a good conversation piece amongst royal enthusiasts. Other than the topic if Charles will ever be the king or will he ever abdicate for his son, Prince William, another interesting topic in one forum is the question on what will happen to Camilla Parker Bowles when Prince Charles dies before he even becomes the king.
Camilla, currently, holds two royal titles: the Duchess of Cornwall and the Duchess of Rothesay in Scotland. Her official title was supposed to be the Princess of Wales since her husband is the Prince of Wales. However, Camilla opted not to use the title out of respect for Prince Charles' ex-wife, Princess Diana.
Camilla is expected to be given the title Queen or Princess Consort once Charles took the throne. However, the Palace will reportedly consider the public reaction when they announce the Queen title of Camilla. Former royal butler Grant Harrold, earlier, told Express UK that the royal family could change its decision to make Camilla Queen if there will be a public outcry.
In the case of Queen Elizabeth II outliving her son, Camilla will remain HRH The Duchess of Cornwall while Prince Charles' titles, the Duke of Cornwall and Duke of Rothesay, will fall in "abeyance" until Prince William becomes king. The titles will go to William's son, Prince George.
If Camilla's path to Queendom is already complicated when her husband ascends to the throne after her mother, Queen Elizabeth II, it will become more complex if Charles dies before kingship and his firstborn child, William, stepped in as king of the monarch.
When that happens, Camilla may not earn the title Queen Mother. This is because she is not the biological mother of William. The title is only given to given to the widow of the king and the mother of the monarch.
However, some argue that, since she is the stepmother of William, it qualifies her for the title in a way. Still, the decision to make her a queen will lie in the hands of Prince William. If Kate Middleton's husband decides not to give Camilla the title of Queen Mother after the death of Charles, then, his stepmother will most likely remain the Duchess of Cornwall.
One Quora user stated that Camilla could also be given the title Her Royal Highness The Dowager Princess of Wales. But, since she already opted not to use the Princess of Wales title, she would likely opt for the equivalent modification of her current title: Her Royal Highness The Dowager Duchess of Cornwall.