Prince Harry’s latest trip to the U.K. to support a close cause won’t include a visit with his father King Charles or brother Prince William.

On Sept. 30, the Duke of Sussex, 40, will step out to attend the 2024 WellChild Awards ceremony in London, bringing him back to England from his California home for the second time in recent weeks. WellChild works to support seriously ill children and their families, and the awards celebrate the inspirational qualities of the young people and their carers. Prince Harry has been patron of the national charity for 16 years, and the awards are a staple on his annual calendar.

PEOPLE understands that the Duke of Sussex has no plans to see the King, 75, or the Prince of Wales, 42, while in London for WellChild. They also didn’t see one another during Prince Harry’s visit to the U.K. in May for an anniversary service commemorating 10 years of his Invictus Games. However, Harry extended invitations to his father and brother ahead of the May event.

Harry’s relationship with his father, who is likely still in Scotland alongside Queen Camilla, remains strained amid the Duke of Sussex’s ongoing battle for security. Sources previously told PEOPLE that calls and letters to his father go unanswered. Harry’s attempts to connect with his brother, William — through texts, calls, and messages — are also similarly ignored.

The family rift, which first became public in 2020 when Prince Harry and his wife, Meghan Markle, stepped back from their royal roles has been marked by blistering attacks and unresolved tensions. For Harry, no single issue is a greater sticking point than that of security, multiple well-placed insiders in his circle told PEOPLE in August.

The Duke of Sussex’s spokesperson attributed the lack of interaction between Harry and his father in May to the monarch’s “full schedule,”  though sources close to the duke hinted at a deeper issue. Prince Harry wanted to discuss his ongoing battle for security, which he has been fighting for in court for over four years and believes his father the King has the power to reinstate. (Buckingham Palace will not comment on security provisions, but a palace source told PEOPLE the notion that Harry’s security is in Charles’ hands is “wholly incorrect.”)

Despite a positive meeting in person between the father and son in February following King Charles’ cancer diagnosis, their communication has since deteriorated. Those close to Harry say that his father no longer takes his son’s calls or responds to his letters. The rift with Prince William is “very bad,” a royal insider said, but it’s not “irreparable.”

Prince Harry and Prince William were at the same place at the same time in late August, when both brothers attended the memorial service for their late maternal uncle, Lord Robert Fellowes, in Norfolk, England. Fellowes was married to Princess Diana’s sister, Lady Jane Spencer, and died in July at age 82, and Prince Harry traveled across the Atlantic to pay his respects at the service on Aug. 29.

During the memorial at St. Mary’s Church in Snettisham, the estranged brothers reportedly avoided each other during the service, each sitting with different groups of their maternal cousins.

“Most people were astounded that Harry came,” one of the reported 300 attendees told PEOPLE. “He was on remarkably good form — and you could tell he was very pleased to see everybody. And he was very pleased that he had come over.”

PEOPLE further learned that the Duke of Sussex stayed with his uncle, Charles Spencer, at Althorp House following his appearance at the memorial service. Althorp is the Spencer family’s ancestral home, where Princess Diana grew up and where the late Princess of Wales is buried. The service for the late Lord Fellowes was held two days before the 27th anniversary of Diana’s death on Aug. 31.

Looking ahead to Prince Harry’s latest U.K. stay (which follows his busy trip to New York City last week to support several of his patronages and philanthropies), he likely won’t be in the U.K. for long after the WellChild ceremony. On. Sept. 27, his charity Sentebale announced that the Duke of Sussex would be in Lesotho in early October, re-convening with his Sentebale co-founder, Prince Seeiso of Lesotho and local Sentebale leaders to highlight programming for the organization dedicated to helping young people in southern Africa.

Amid what’s expected to be a short U.K. trip for Harry, King Charles and Queen Camilla are in Scotland. The royal couple traveled north to mark the 25th anniversary of the Scottish Parliament on Sept. 28, and likely will not be back in London on Monday.