Prince William and Camilla are taking charge amid King Charles' absence. Is it sustainable?

The British royal family has kept tradition in its ability to "keep calm and carry on" amid rare public disclosures of health concerns.

King Charles III, who is being treated for an undisclosed form of cancer, and Princess Kate, who is recovering from abdominal surgery, have left holes in appearances and charitable acts in their normally robust schedules.

Prince William and Queen Camilla have been steadfast in their commitment to public duties in the month since their respective spouses were hospitalized, but that hasn't come without a few intermissions.

The Prince of Wales was absent at the memorial service for his godfather, the late King Constantine of Greece, at St. George's Chapel on Feb. 27 and resumed duties shortly after. Kensington Palace stated that William could not attend the memorial because of a personal matter, further fueling online theories about Kate's health and whereabouts.

The Princess of Wales hadn't been seen publicly since December for a Christmas church service at St. Mary Magdalene Church. On Monday, photos obtained by TMZ claimed to show her for the first time.

Camilla also is taking a break, according to The Times and Fox News, gearing up for her prominent role on Commonwealth Day on March 11.

William and Camilla have not shown or conveyed that the task load in Charles' slimmed-down monarchy is unmanageable thanks to extended family members stepping up, according to experts.

Royal expert and Majesty magazine managing editor Joe Little says that so far, "there's nothing yet to suggest that the queen and the Prince of Wales's workload has increased, or will increase in the short term, as a consequence of the king having to cancel public-facing duties. Likewise for the other working members of the royal family."

Prince William and Queen Camilla are doing 'business as usual' amid King Charles III and Princess Kate's health concerns

For the most part, the royal duties continue to be handled with typical stiff-upper-lip resolve, says Little, even if the reigning monarch is going through a health crisis that certainly weighs on all the royals.

"On a personal level, Camilla and William are obviously concerned about the king's ill health and with that comes a degree of stress, but it's business as usual as far as everyone is concerned," he adds.

The challenges facing both William and his stepmother, Camilla, are very real and, in some ways, not unlike those of any family trying to juggle a host of responsibilities when a key family member is suddenly indisposed, agrees Carolyn Harris, co-editor of "English Consorts: Power, Influence and Dynasty," and a professor at the University of Toronto School of Continuing Studies.

Prince William pulls out of godfather's memorial service for personal matter amid Kate absence

"In the coming weeks, Prince William will have a very busy schedule of both personal and public responsibilities," she says. As for Camilla, the queen consort "has maintained a strong public profile in recent weeks, making frequent public appearances and emphasizing that the king is doing well under circumstances."

Washington, D.C.-based psychotherapist Dr. Victor Kidd echoes Harris' statements about how the royal family is likely dealing with stress and grief amid health struggles, adding that "the social position that people operate has no impact on the very real human experience."

"We have to be mindful that just because they're the royal family, that doesn't make them aliens or that they're no longer human beings," Kidd says.

Despite hesitance to publicly address health issues, Kidd says the royal family may face some struggles. "When you think about terminal illness or even death, those things really have a unique way of humanizing us and putting us in a place where we look at mortality."

Extended members of the royal family have stepped up amid King Charles III and Princess Kate's absences

Their ability to maintain stamina has been a full family effort.

"Other working members of the royal family are providing valuable contributions to the monarchy's public profile," says Harris. "For instance, Princess Anne undertakes extensive overseas travel on behalf of her brother King Charles III. Edward and Sophie, the Duke and Duchess of Edinburgh, also have a full schedule of public engagements and have taken on charitable patronages, such as the Duke of Edinburgh award, that were established by the late Prince Philip."

Even some of the older royals are likely to step in, she says."Although the late Queen Elizabeth II's cousins are now in their 70s and 80s, they continue to undertake some royal engagements, especially the Duke and Duchess of Gloucester. The queen's 79-year-old cousin, Prince Richard, Duke of Gloucester, has been active during the early months of King Charles III's reign, attending state dinners and garden parties with his wife Brigitte, the Duchess of Gloucester," Harris adds, noting Brigitte's appearance with Camilla as they co-presented the the Queen's Anniversary Prizes for Higher and Further education at Buckingham Palace on Feb. 22.

Are William and Camilla's added responsibilities sustainable?

That juggling act is about to get more difficult, Harris says, should Charles continue to focus on his health as the winter months give way to a busy spring and summer of royal activities.

"Prince William and Queen Camilla will likely have additional responsibilities as the royal garden party season begins and the number of public receptions at royal palaces increases," she says.

Charles' cancer diagnosis came after the king underwent a hospital procedure for benign prostate enlargement. The palace said he has "commenced a schedule of regular treatments" and would be postponing his public-facing duties.

He was seen last week in his first meeting with U.K. Prime Minister Rishi Sunak at Buckingham Palace since the diagnosis. The monarch expressed his gratitude for the kind words he has received, in video filmed by Sky News. The prime minister told Charles it was "wonderful to see you looking so well."

Kidd says this period of the royal family grappling with private health issues in public is likely bonding Camilla to the king and William to Kate.

"The royal family is experiencing and doing it as a pair or as a partnership, it could really bring forth some strengths, and it could also improve some weaknesses that might have been there prior to this," he says.

Commonwealth Day to be a key indicator of the British monarchy's health

The United Kingdom's annual Commonwealth Day on March 11 will reveal more about how the family is coping and whether the public has faith in the monarchy.

On March 3, Buckingham Palace announced that Camilla and William will helm responsibilities for the day at Westminster Abbey alongside other royals. Notably, the king's presence is not expected.

The day celebrates the connection, however under threat, between the monarchy and the various nations it remains linked to, such as Australia, India and several Caribbean islands and African countries.

"There will be increased scrutiny of the royal family at the Commonwealth Day service as this is an occasion that brings the working members of the royal family together," says Harris.

Princess Anne, Prince Edward and Queen Elizabeth II's cousins Prince Richard and Prince Edward, Duke of Kent, are among the working royals to be in attendance.

In an extreme case, "there may be changes to the 2024 royal schedule including postponement of Commonwealth tours," she speculates.

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At last year's Commonwealth Day, Charles spoke about his hopes for the future of the Commonwealth amid the Charter of the Commonwealth's 10th anniversary, centering "peace and justice; tolerance, respect and solidarity; care for our environment, and for the most vulnerable among us."

With the Commonwealth ruling over a third of the world's population, Charles said he hopes to tackle issues on "climate change and biodiversity loss, youth opportunity and education, global health, or economic cooperation" with a collaborative effort from fellow countries.

Prince William likely to step up amid King Charles III's cancer diagnosis, experts say

Contributing: The Associated Press

This article originally appeared on USA TODAY: Prince William, Queen Camilla are remaining strong. Is it sustainable?