I know Diana was Charles ex, but she was the mother of his two sons. Surely they could just issue a joint bland statement acknowledging her untimely death and the impact on William and Harry?
To pretend it is not even happening would be pretty crass.
"Incredibly, however, the royal family has no plans to formally commemorate the 25th anniversary of the death of Princess Diana on Wednesday next week—illustrating, some would say, just how threatened they still are by her, even in death.
While her sons are widely expected to issue, at a minimum, online tributes, Prince Charles, who conducted an affair with his second wife, Camilla Parker Bowles, both before and throughout much of his marriage to Diana, which Diana publicly blamed for the collapse of their relationship, is likely to maintain radio silence."
www.thedailybeast.com/queen-elizabeth-and-prince-charles-have-no-plans-to-mark-25th-anniversary-of-princess-dianas-death