Prince William is following his grandmother Queen Elizabeth’s example as Kate Middleton navigates her cancer diagnosis.

“[William] is incredibly stoic and strong. He took a lot from the way his grandmother operated, and his playbook is modeled on hers.

It’s going to be incredibly difficult. But he is a man who is used to shouldering pressure,” a close palace source tells PEOPLE exclusively in this week’s cover story.

Amid the challenges of his wife and father, King Charles, both having cancer, the Prince of Wales, 41, is looking after his loved ones.

“There will be a lot more pressure on William, but he’s always been aware of that. He has evolved to lead, and he is leading,” says a former palace aide. “He is well-equipped for it and has his priorities in order. In this time of crisis, they’ve been shutting themselves away and focusing on family and the children. That is what the Queen did when Diana died — despite the criticism.”

In the days following Princess Kate’s shocking health announcement, she and Prince William remained focused on their children, Prince George, Princess Charlotte and Prince Louis, who are currently on Easter break from school. The family of five will shift tradition by opting out of the royals’ Easter services at Windsor Castle on Sunday and instead spend the weekend privately at home.

Prince William will resume public duties after the children return to school later in April, and Princess Kate will remain out of the public eye during treatment she described as “preventative chemotherapy.” For now, her focus is on her full recovery with her family around her.

“She has the inner strength, the support of her husband and her extraordinary family, so she can focus on what’s important,” says Ailsa Anderson, a former spokeswoman for Queen Elizabeth, “which is her getting back to strength.”

Anderson adds that Prince William will be the “anchor” for his young family and points to the timing of the public announcement, which was strategically released when George, 10, Charlotte, 8, and Louis, 5, were already off from school for the Easter holiday.

“They are protecting their children. They are thinking about their welfare above everything,” she says.

In the vulnerable video message, which was filmed in the garden of Windsor Castle last Wednesday, Princess Kate said that “it has taken us time to explain everything to George, Charlotte and Louis in a way that is appropriate for them, and to reassure them that I am going to be okay.”

The Princess of Wales, 42, chose to deliver the news solo, prompting some to wonder why Prince William didn’t join her. A palace source tells PEOPLE it was important to Kate to “personally deliver the message on her own,” adding that Kate made clear that her husband has been “supporting her throughout.”

“William is extremely proud of his wife for the courage and strength she has shown not just this week but since her surgery in January,” the source says. “Now more than ever, he’s focused on ensuring his wife has the privacy she needs to fully recover and that his children are shielded from the understandable interest in the news that has been shared.”