Prince William (41) shared his thoughts and experiences about what the sudden loss of a loved one means – even after a long time. In a new brochure designed to help grieving families, the heir to the British throne writes, according to the Daily Mail: “No two experiences of grief are ever the same.” The 41-year-old added: “The sudden and often unexpected loss of a loved one can be extremely difficult to come to terms with, even as time passes,” said the Prince of Wales.

According to the report, William wrote the foreword for the brochure, which was put together by the London Air Ambulance Charity. The son of King Charles III. (74), who is the organization’s patron, said he hoped the booklet would provide some “comfort and support.” In it he wrote to the grieving people “whose world is now completely different” that his thoughts were with them.

In the brochure, relatives remember deceased family members and report on their experiences. Prince William thanked them for sharing their “most precious memories.” The royal added, according to the Daily Mail: “You can find some comfort in sharing experiences.”

Prince William lost his mother, Princess Diana (1961-1997), when he was just 15 years old. On August 31, 1997, the ex-wife of the current King Charles III. together with her new love, the businessman and Harrods heir Dodi Al-Fayed (1955-1997), and her bodyguard Trevor Rees-Jones (55) traveling in a Mercedes limousine when the car entered the Pont de l’Alma tunnel crashed into a concrete pillar in Paris.

Dodi Al-Fayed and the driver of the car, Henri Paul (1956-1997), died at the scene of the accident. Trevor Rees-Jones survived with serious injuries, including to his head. Diana was pronounced dead in hospital at 4am. She was only 36 years old.