King Charles III‘s nephew, Peter Phillips, is giving insight into how the most senior member of the British monarchy is doing amid his cancer treatment. 

In a new interview with Sky News Australia, the 46-year-old son of Princess Anne and her first husband, Captain Mark Phillips, said that the U.K. reigning monarch, 75, is upset over the timeline of his recovery but “pragmatic” about the medical advice he has been given. 

“He’s in good spirits,” Phillips told the Aussie outlet. “I think, ultimately, he’s hugely frustrated. He’s frustrated that he can’t get on and do everything that he wants to be able to do.”

Buckingham Palace announced in February that Charles had been diagnosed with cancer following a procedure he underwent for an enlarged prostate. The Palace has not shared what type of cancer Charles is battling or when he is expected to resume his typical royal duties. Since the diagnosis, he has been receiving treatment and recuperating at Sandringham Estate.

“The King is grateful to his medical team for their swift intervention, which was made possible thanks to his recent hospital procedure,” Buckingham Palace shared in a statement in February. “He remains wholly positive about his treatment and looks forward to returning to full public duty as soon as possible.”

While Kate Middleton has fully stepped back from her role as a senior working royal after her winter abdominal surgery and amid her recent cancer diagnosis, Charles has been tackling his work on a scaled-back basis, working mostly on state business and paperwork, the Palace stated. 

Phillips said the king is eager to get back to work and thus has been putting pressure on himself and those around him to hurry his progress along. 

“He is always pushing his staff and everybody and his doctors and nurses to be able to say, ‘Actually come on, you know, can I do this? Can I do that?'” the king’s nephew told the Australian outlet. “But he is very pragmatic [and] he understands that there’s a period of time that he really needs to focus on himself.”

Amid his treatment, Charles’ wife, Queen Camilla, and his eldest son, Prince William, have both taken on additional responsibilities and royal duties.

Just last week, Princess Eugenie shared an update on her grandfather’s health and cancer battle, telling reporters at an Elephant Family charity event that he was in good spirits.

“He’s doing well,” Eugenie, 34, said.

The timeline for Charles’ return is unclear and ET recently learned that he will be enjoying scaled-down Easter festivities at Sandringham with William, Kate, and their three children, Prince George, 10, Princess Charlotte, 8, and Prince Louis, 5.

For more on King Charles and Princess Kate’s cancer diagnoses, check out the links below. 

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