Prince William and Prince Harry's rift is unlikely to heal anytime soon despite hopes that their father King Charles III's cancer diagnosis could bring the estranged brothers together, according to a royal commentator.

After a brief visit with King Charles, the Duke of Sussex reportedly returned to California Wednesday without seeing Prince William.

Royal commentator Daniella Ralph said this suggests a reconciliation between the siblings is unlikely to happen at the moment.

"It's a sibling relationship that still looks incredibly broken," she said, according to GB News.

Ralph noted, "We don't know if either side has reached out in any way, if there has been any attempt to find a truce. As things stand, there doesn't seem to be any sign of that."

Prince William, Prince Harry, Meghan Markle and Prince Charles
(Photo : RICHARD POHLE/POOL/AFP via Getty Images)
Prince William, Prince Harry, Meghan Markle and Prince Charles attend the Commonwealth Day service at Westminster Abbey in London on March 11, 2019. 

Prince Harry's one-day visit to the U.K. included a reported 45-minute meeting with King Charles at Clarence House on Tuesday afternoon, but he did not see Prince William during the short stay, the Daily Mail reported.

The Duke of Sussex reportedly boarded a flight from Heathrow Airport back to the U.S. Wednesday, according to the outlet.

People reported earlier this week that Prince Harry's trip did not include plans to meet with his older brother.

Like Ralph, English broadcaster Piers Morgan also believes that reconciliation is not happening anytime soon for the estranged brothers.

"I think William would rather shoot himself than see his brother right now," Morgan said on "Today." "I think this is very deep. This is a real sibling war."

Prince William and Prince Harry's relationship reportedly has been strained since the latter stepped back from his role as a working royal in 2020 and moved to the U.S. with his wife, Meghan Markle.

The tension in the brothers' relationship reportedly worsened after the release of Prince Harry's 2023 memoir, "Spare," which contained criticisms and accusations against Prince William, including allegations of a physical attack.

Kate Middleton, Prince William and Prince Harry
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Kate Middleton, Prince William and Prince Harry take part in a relay race, during a training event to promote the charity Heads Together, at the Queen Elizabeth Olympic Park in London, on February 5, 2017.

Amid his younger brother's U.K. visit, Prince William resumed his royal duties Wednesday.

Conducting a morning of investitures at Windsor Castle, the Prince of Wales presented medals to individuals recognized for outstanding achievement, personal bravery, or services to the U.K.

Later in the day, he attended the London's Air Ambulance Charity Gala Dinner.

Addressing the public support his family received following a series of health announcements, Prince William expressed gratitude, stating, "We really appreciate everyone's kind messages. Thank you," as quoted by People.

Prince William's wife, Kate Middleton, had undergone "planned abdominal surgery" on Jan. 17, leading to her husband clearing his calendar to support her and their three children.

The palace stated that Princess Kate is unlikely to return to public duties until after Easter.

Britain's Prince William, Prince of Wales and Britain's Catherine, Princess of Wales Kate Middleton
(Photo : Getty Images/Aaron Chown/POOL/AFP)
Britain's Prince William, Prince of Wales and Britain's Catherine, Princess of Wales applaud during the Royal Variety Performance at the Royal Albert Hall in London on November 30, 2023.

On Monday, Buckingham Palace announced that King Charles had been diagnosed with cancer, prompting him to postpone public-facing duties.

Despite undergoing treatment, the palace emphasized that the monarch would continue state business and official paperwork.

Remaining optimistic about his treatment, King Charles aims to return to full public duty as soon as possible, according to the palace.