An aunt of Prince William and Prince Harry is recovering after a “really bad” fall from her horse.

Lady Sarah McCorquodale, who is the eldest sister of the late Princess Diana, fell and seriously injured herself last month.

Her brother Charles Spencer revealed the accident during a chat on the Rosebud with Gyles Brandreth podcast on Friday, Oct. 24. Describing the incident, Charles said of Lady Sarah, 70: “She’s still riding, and she’s had a really bad fall last month and has been in hospital for a long time.”

“I think, [she] was quite a handful as a patient, because the lead doctor said to my brother-in-law, ‘She’s quite a character isn’t she?’ ” the 61-year-old said, referring to Sarah’s husband Neil McCorquodale. “Which I think is code for, ‘Could you take her home?’ ”

A friend tells PEOPLE that Lady Sarah “is on the mend.”

Charles, who is the 9th Earl Spencer, said his sister was “always in trouble” when they were growing up at the family’s stately home, Althorp. She was “quite punchy,” he told podcast host Brandreth, 77.

One day, when in the midst of an argument with their father, Charles recalled how Lady Sarah “rode her horse into the hall” of their home and simply stayed there. It was, her brother said, “a brilliant gesture because what are you going to do with that?”

Like her sister Lady Jane Fellowes, 68, Lady Sarah has stayed close with her nephews, William, 43, and Harry, 41. In September 2024, she made a rare appearance alongside William as she supported him at RAF Cranwell, where the prince was honoring graduates at the flight training school where he had also been tutored.

Lady Sarah was one of the committee members helping commission and manage the process of the statue erected in tribute to her late sister in 2021. On July 1 of that year, on what would have been Diana’s 60th birthday, Lady Sarah was joined by her siblings Charles and Lady Jane when William and Harry unveiled the statue in the grounds of Kensington Palace. Harry returned from California for the occasion.

In 2019, she and Lady Jane also attended the christening of Harry and his wife Meghan Markle’s son Prince Archie at Windsor.

Princess Diana died at the age of 36 following a car crash in Paris on Aug. 31, 1997. During his appearance on the podcast, Charles also spoke about writing what became one of the most famous eulogies of the last century.

He told Brandreth that he initially wondered who would be the right person for the immensely moving task. “I had a big, thick address book, and I thought, ‘I want to find someone who’s going to make the speech for her.’ And I got to ‘Z’ and I hadn’t found anyone,” Charles said.

“[I] got off the plane in Heathrow [Airport], called my mother, I said, ‘I can’t think who’s going to give the eulogy. And I’ve got an awful feeling it’s going to have to be me,’ ” he continued. “And she said, ‘Well, it is going to be you. Your sisters and I have decided it.’ ”